CPC · California Plumbing Code

When is backflow protection required on a potable water service?

Q: Is an air gap always the preferred protection method?

An air gap is the most fail‑safe method because it physically separates the potable supply; where practicable and code‑allowed it is acceptable. Where an air gap is impractical or not permitted by the fitting/installation, listed backflow assemblies (vacuum breakers, PVB, RP, etc.) are used per the applicable CPC subsection (see § 603.5.5 and Table 603.2) file.

Plain English summary for a homeowner: The California Plumbing Code requires you to protect your drinking water whenever a connection could let contaminated water flow back into the house supply — for example irrigation systems with pumps or chemical injectors, pools, or equipment that adds chemicals. The code lists which devices to use (vacuum breakers, pressure vacuum breakers, or reduced‑pressure backflow preventers) depending on the risk; for high‑risk or backpressure situations you must use a reduced‑pressure (RP) assembly. The guidance above is based on the CPC Chapter 6 backflow sections (notably § 603.5 series) in the materials provided; I could not find the specific text of § 602.0–§ 602.3 in your uploaded files, so if you want a direct mapping to those exact sections please upload them and I will re‑anchor each item to those paragraphs. file

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Last reviewed: July 6, 2026

What the code requires — plain English (controlling §)

The California Plumbing Code requires that a potable water supply be protected from backpressure and backsiphonage (cross‑connections) by installing an approved backflow prevention method appropriate to the degree of hazard. The detailed device choice depends on the use (irrigation, pools, chemical injectors, fire protection, pure‑water processes, etc.) rather than a single universal rule; see § 603.5 series for specific situations such as irrigation, tanks, pools, fire systems and pure water processes (for example § 603.5.5 and § 603.5.6) .

Note: I attempted to retrieve the text of the sections you listed as controlling — § 602.0, § 602.1, § 602.2, and § 602.3 — but those specific sections were not present in the files you uploaded, so I cannot quote or ground rules directly to those four section texts. Instead this guidance is grounded in the available Chapter 6 backflow provisions (notably the § 603.5 series) from the CPC that address when and what type of backflow protection is required .

The single most important rule: protect any potable water connection that can be contaminated by a nonpotable source or that can create backpressure — pick the backflow device rated for the degree of hazard named in Chapter 6. See § 603.5 for specific situations and device types.

Requirements in detail

Key defined terms (first appearance bolded)

Potable water supply — water intended for human consumption.
Backpressure — pressure on the downstream side that can push contaminants into the potable system.
Backsiphonage — negative pressure (suction) that can draw contaminants into the potable system.
Degree of hazard — whether contamination is health (high) or nonhealth (low/lesser) related; device selection follows the hazard.

Decision dimensions

Use the table below to determine when protection is required and what device types the CPC names (decision factors → device). The "Code Reference" column points to the CPC section(s) found in the uploaded files that specify the requirement.

Situation / decision factor	Typical required protection (device type)	Code Reference
Water supply inlets to tanks, vats, pools, sumps (possible contamination)	Air gap, or listed vacuum breaker, or backflow preventer commensurate with hazard	§ 603.5.5
Lawn irrigation / sprinklers (no pumps, no chemical injectors)	Atmospheric vacuum breaker (AVB), Pressure vacuum breaker (PVB), Spill‑resistant PVB (SVB), or Reduced‑pressure (RP)	§ 603.5.6
Irrigation systems that have pumps, booster connections, auxiliary air tanks, or can create backpressure	Reduced‑pressure principle backflow prevention assembly (RP) (when device is upstream from source of backpressure)	§ 603.5.6.1
Systems with chemical injectors or provisions for injection	Reduced‑pressure principle backflow prevention assembly (RP)	§ 603.5.6.3
Swimming pools / spas with submerged fill or direct connection to circulation	Air gap or Reduced‑pressure (RP)	§ 603.5.21
Pure water process systems (e.g., dialysis, semiconductor wash)	Reduced‑pressure (RP)	§ 603.5.18
Fire protection systems (direct connection) — ordinary class systems	Backflow protection at service per NFPA standards (see local adoption). If antifreeze or nonpotable source present, RP or reduced‑pressure detector assembly	§ 603.5.14, § 603.5.14.2
Beverages / food equipment (carbonated, non‑carbonated)	Air gap, vented backflow preventer, dual check, or devices listed to ASSE standards as specified in Table 603.2	§ 603.5.12 and Table references (Table 603.2)
Manufactured home lot with cross‑connection condition	Listed backflow preventer at or near the service outlet; pressure‑relief valve on discharge side where installed	E 302.4, E 302.5

(If a precise device standard is required, refer to Table 603.2 and the ASSE/IAPMO standards referenced in CPC Chapter 17 and Table listings.)

How to pick the device (short flow)

Step 1 — Identify the hazard (health vs. non‑health) and whether the system can develop backpressure or backsiphonage.
Step 2 — Consult the specific CPC subsection for that use (e.g., irrigation § 603.5.6, pools § 603.5.21, pure‑water § 603.5.18). Use the most protective device required for the hazard (RP for health‑hazard/chemical injection) .
Step 3 — Install in the location required by the code and manufacturer listing; account for test/maintenance access and hydraulic pressure drop (fire systems note) .

Exceptions & special cases

Fire sprinkler systems that meet the listed NFPA criteria may have different service‑connection rules; where antifreeze or chemical additives are present the CPC requires RP protection (see § 603.5.14.2) .
Some small, temporary above‑ground irrigation or roof‑spray systems may be exempt from dedicated metering or different rules in the residential code; check the applicable residential provisions (R309 series) for exceptions .
The uploaded CPC excerpts do not contain the explicit text of § 602.0–§ 602.3; if those sections are the local controlling sections in your jurisdiction, supply them and I will map requirements straight to those paragraphs. At present, the operative backflow requirements in the materials I can access are in the § 603.5 series and related tables/appendices .

Common mistakes

Assuming an AVB is acceptable where the system can develop backpressure (AVB only protects against backsiphonage; CPC requires RP where backpressure is possible — see § 603.5.6.1) .
Installing backflow devices underground or below frost/sump level where they cannot be serviced — CPC prohibits underground installation of certain outlets and indicates mounting/access requirements (see § 603.5.17 and E 302.5 guidance for clearances) file.
Forgetting to account for the pressure drop through a backflow assembly when sizing for fire protection hydraulics — CPC explicitly requires checking the sprinkler hydraulics when a device is added or retrofitted (§ 603.5.14.3) .
Using a device not listed to the standards referenced by CPC (Table 603.2 / referenced ASSE/IAPMO standards) — the code requires listed devices where noted .

Worked example — concrete scenario

Scenario: A commercial landscape irrigation system is directly supplied from the building potable service. The irrigation includes a booster pump to raise pressure for higher zones and has a chemical injector connection for fertilizer.

Step 1 — Identify hazards: pump → potential backpressure; chemical injector → chemical hazard (health‑related).
Step 2 — Code requirement: Because the system has a pump (creates backpressure) and chemical injection, the CPC requires protection by a reduced‑pressure principle backflow prevention assembly (RP) (the CPC requires RP where pumps/backpressure exist upstream of device and where chemical injectors/provisions are present) — see § 603.5.6.1 and § 603.5.6.3 .
Step 3 — Installation notes: place the RP where it isolates the potable supply (upstream of the irrigation pump if the device must be upstream from the source of backpressure), provide service access and locking, and account for the device pressure loss in the system design. Test annually/periodically per local AHJ/tester qualifications (P 102 series) file.

Numeric check example (simplified): If the pump creates 20 psi of backpressure potential and the RP imposes a 10 psi pressure loss at operating flow, the designer must ensure downstream zones still get adequate pressure by adding the 10 psi loss into hydraulic calculations (CPC requires hydraulics be checked for sprinkler/fire systems when a device is added — § 603.5.14.3; analogous consideration applies for irrigation) .

Related provisions (CPC sections you should check)

§ 603.5.5 — Water supply inlets to tanks, vats, pools; air gap, vacuum breaker, or appropriate backflow preventer required .
§ 603.5.6 — Protection for lawn sprinklers and irrigation systems; device types listed .
§ 603.5.6.1 — Systems with pumps: RP required where backpressure source exists .
§ 603.5.6.3 — Systems with chemical injectors: RP required .
§ 603.5.14 / § 603.5.14.1–.3 — Protection related to fire protection systems, fire department connections, and chemicals; hydraulic design note for backflow devices on fire systems .
§ 603.5.18 — Pure water process systems: RP required .
§ 603.5.21 — Swimming pools, spas, and hot tubs: air gap or RP required where submerged fill or direct connection exists .
E 302.4 / E 302.5 — Manufactured home park lot backflow and pressure‑relief valve requirements (appendix provisions) .
Table 603.2 and Chapter 17 referenced standards — consult for device listings and ASSE/IAPMO standards to be used (e.g., ASSE 1013 for RP, ASSE 1015 for double check, etc.) .

Code references

Grounded in the retrieved California Plumbing Code — click a citation to read the verbatim passage:

CPC § 3.5.3 High relevance — show source text

2.4. A sign shall be provided stating “Valve must be opened monthly for 5 minutes.” 2.5. A means for automatically refilling the tank level so that the tank capacity will meet the required water supply duration in minutes shall be provided.

R309.3.5.3 Connections to automatic fire sprinkler systems. The potable water supply to automatic fire sprinkler shall be protected against backflow by a double check backflow prevention assembly, a double check fire protection backflow prevention assembly, a reduced pressure principle backflow prevention assembly or a reduced pressure principle fire protection backflow prevention assembly.

Exception: Where permitted by Section R309.3.1.1, backflow protection for the water supply system shall not be required.

R309.3.5.3.1 Additives or nonpotable source. Where systems contain chemical additives or antifreeze, or where systems are connected to a nonpotable secondary water supply, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly or a reduced pressure principle fire protection backflow prevention assembly. Where chemical additives or antifreeze is added to only a portion of an automatic sprinkler or standpipe system, the reduced pressure principle fire protection backflow preventer shall be permitted to be located so as to isolate that portion of the system.

R309.3.6 Pipe sizing. The piping to sprinklers shall be sized for the flow required by Section R309.3.4.2. The flow required to supply the plumbing fixtures shall not be required to be added to the sprinkler design flow.

R309.3.6.1 Method of sizing pipe. Piping supplying sprinklers shall be sized using the prescriptive method in Section R309.3.6.2 or by hydraulic calculation in accordance with NFPA 13D. The minimum pipe size from the water supply source to any sprinkler shall be [3] / 4 inch (19 mm) nominal. Threaded adapter fittings at the point where sprinklers are attached to the piping shall be not less than [1] / 2 inch (13 mm) nominal.

R309.3.6.2 Prescriptive pipe sizing method. Pipe shall be sized by determining the available pressure to offset friction loss in piping and identifying a piping material, diameter and length using the equation in Section R309.3.6.2.1 and the procedure in Section R309.3.6.2.2 .

2025 CALIFORNIA RESIDENTIAL CODE 3-45

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

BUILDING PLANNING

TABLE R309.3.6.2(1)—WATER SERVICE PRESSURE LOSS (PL ) a, b svc	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10	Col11	Col12	Col13
FLOW RATEc (gpm)	3/4-INCH WATER SERVICE PRESSURE LOSS (psi)	3/4-INCH WATER SERVICE PRESSURE LOSS (psi)	3/4-INCH WATER SERVICE PRESSURE LOSS (psi)	**3/4-INCH

CPC § 603.5.14.1 High relevance — show source text
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

WATER SUPPLY AND DISTRIBUTION

(1) American Water Works Association [A.W.W.A] Manual No. M-14 class 1 – Automatic fire sprinkler systems with direct connection from public water mains only; no pumps, tanks, or reservoirs; no physical connection from other water supplies; no antifreeze or additives of any kind; and all sprinkler drains discharging to the atmosphere or other safe outlets.

(2) American Water Works Association [A.W.W.A] Manual No. M-14 class 2 – Automatic fire sprinkler systems which are the same as class 1, except that booster pumps may be installed in the connections from the street mains.

(b) Automatic fire sprinkler systems described in subdi- vision (a) shall not require any backflow protection equipment at the service connection other than required by standards for those systems contained in the publication of the National Fire Protection Association entitled “Installation of Sprinkler Sys- tems” [NFPA Pamphlet No. 13, 1980 edition]. 603.5.14.1 Fire Department Connection. Where fire protection systems supplied from a potable water system include a fire department (siamese) connection that is located less than 1700 feet (518.2 m) from a nonpotable water source that is capable of being used by the fire department as a secondary water supply, the potable water supply shall be protected by one of the following:

(1) Reduced pressure principle backflow prevention assembly (RP)

(2) Reduced pressure detector fire protection backflow prevention assembly

Nonpotable water sources include fire department vehicles carrying water of questionable quality or water that is treated with antifreeze, corrosion inhibitors, or extinguishing agents. 603.5.14.2 Chemicals. Where antifreeze, corrosion inhibitors, or other chemicals are added to a fire protection system supplied from a potable water supply, the potable water system shall be protected by one of the following:

(1) Reduced pressure principle backflow prevention assembly (RP)

(2) Reduced pressure detector fire protection backflow prevention assembly 603.5.14.3 Hydraulic Design. Where a backflow device is installed in the potable water supply to a fire protection system, the hydraulic design of the system shall account for the pressure drop through the backflow device. Where such devices are retrofitted for an existing fire protection system, the hydraulics of the sprinkler system design shall be checked to verify that there will be sufficient water pressure available for satisfactory operation of the fire sprinklers. 603.5.15 Health Care or Laboratory Areas. Vacuum breakers for washer-hose bedpans shall be located not less than 5 feet (1524 mm) above the floor. Hose con

nections in health care or laboratory areas shall be not less than 6 feet (1829 mm) above the floor. 603.5.16 Special Equipment. Portable cleaning equipment and dental vacuum pumps shall be protected from backflow by an air gap, an atmospheric vacuum breaker, a spill-resistant vacuum breaker, or a reduced pressure principle backflow preventer.

**603.5.17 Potable Water Outlets and Valves.
CPC § 603.5.2 High relevance — show source text
603.5.2 Ballcock. Water closet and urinal tanks shall be equipped with a ballcock. The ballcock shall be installed with the critical level not less than 1 inch (25.4 mm) above the full opening of the overflow pipe. In cases where the ballcock has no hush tube, the bottom of the water supply inlet shall be installed 1 inch (25.4 mm) above the full opening of the overflow pipe.

603.5.3 Backflow Prevention. Water closet flushometer tanks shall be protected against backflow by an approved backflow prevention assembly, device, or method.

603.5.4 Heat Exchangers. Heat exchangers used for heat transfer, heat recovery, or solar heating shall protect the potable water system from being contaminated by the

heat-transfer medium. Single-wall heat exchangers used in indirect-fired water heaters shall meet the requirements of Section 505.4.1. Double-wall heat exchangers shall separate the potable water from the heat-transfer medium by providing a space between the two walls that are vented to the atmosphere. 603.5.5 Water Supply Inlets. Water supply inlets to tanks, vats, sumps, swimming pools, and other receptors shall be protected by one of the following means:

(1) An approved air gap.

(2) A listed vacuum breaker installed on the discharge side of the last valve with the critical level not less than 6 inches (152 mm) or in accordance with its listing.

(3) A backflow preventer suitable for the degree of hazard, installed in accordance with the requirements for that type of device or assembly as set forth in this chapter. 603.5.6 Protection from Lawn Sprinklers and Irri- gation Systems. Potable water supplies to systems having no pumps or connections for pumping equipment, and no chemical injection or provisions for chemical injection, shall be protected from backflow by one of the following devices:

(1) Atmospheric vacuum breaker (AVB)

(2) Pressure vacuum breaker backflow prevention assembly (PVB)

(3) Spill-resistant pressure vacuum breaker (SVB)

(4) Reduced-pressure principle backflow prevention assembly (RP)

(5) A valve complying with IAPMO PS 72 603.5.6.1 Systems with Pumps. Where sprinkler and irrigation systems have pumps, connections for pumping equipment, or auxiliary air tanks, or are otherwise capable of creating backpressure, the potable water supply shall be protected by the following type of device where the backflow device is located upstream from the source of backpressure:

(1) Reduced-pressure principle backflow prevention assembly (RP) 603.5.6.2 Systems with Backflow Devices. Where systems have a backflow device installed downstream from a potable water supply pump or a potable water supply pump connection, the device shall be one of the following:

(1) Atmospheric vacuum breaker (AVB)

(2) Pressure vacuum breaker backflow prevention assembly (PVB)

(3) Spill-resistant pressure vacuum breaker (SVB)

(4) Reduced-pressure principle backflow prevention assembly (RP) 603.5.6.3 Systems with Chemical Injectors. Where systems include a chemical injector or provisions for chemical injection, the potable water supply shall be protected by a reduced-pressure principle backflow prevention assembly (RP).

2025 CALIFORNIA PLUMBING CODE 141
CPC § 603.5.14.2 High relevance — show source text
(1) Reduced pressure principle backflow prevention assembly (RP)

(2) Reduced pressure detector fire protection backflow prevention assembly

Nonpotable water sources include fire department vehicles carrying water of questionable quality or water that is treated with antifreeze, corrosion inhibitors, or extinguishing agents. 603.5.14.2 Chemicals. Where antifreeze, corrosion inhibitors, or other chemicals are added to a fire protection system supplied from a potable water supply, the potable water system shall be protected by one of the following:

(1) Reduced pressure principle backflow prevention assembly (RP)

(2) Reduced pressure detector fire protection backflow prevention assembly 603.5.14.3 Hydraulic Design. Where a backflow device is installed in the potable water supply to a fire protection system, the hydraulic design of the system shall account for the pressure drop through the backflow device. Where such devices are retrofitted for an existing fire protection system, the hydraulics of the sprinkler system design shall be checked to verify that there will be sufficient water pressure available for satisfactory operation of the fire sprinklers. 603.5.15 Health Care or Laboratory Areas. Vacuum breakers for washer-hose bedpans shall be located not less than 5 feet (1524 mm) above the floor. Hose con

nections in health care or laboratory areas shall be not less than 6 feet (1829 mm) above the floor. 603.5.16 Special Equipment. Portable cleaning equipment and dental vacuum pumps shall be protected from backflow by an air gap, an atmospheric vacuum breaker, a spill-resistant vacuum breaker, or a reduced pressure principle backflow preventer.

603.5.17 Potable Water Outlets and Valves. Potable water outlets, freeze-proof yard hydrants, combination stop-and-waste valves, or other fixtures that incorporate a stop and waste feature that drains into the ground shall not be installed underground. 603.5.18 Pure Water Process Systems. The water supply to a pure water process system, such as dialysis water systems, semiconductor washing systems, and similar process piping systems, shall be protected from backpressure and backsiphonage by a reduced-pressure principle backflow preventer. 603.5.18.1 Dialysis Water Systems. The individual connections of the dialysis related equipment to the dialysis pure water system shall not require additional backflow protection. 603.5.19 Garbage Can Washers. Where garbage can washers are connected to a potable water supply system, the connection shall be protected against backflow in accordance with Table 603.2.

603.5.20 Plumbing Fixture Fittings. Plumbing fixture fittings with integral backflow protection shall comply with ASME A112.18.1/CSA B125.1. 603.5.21 Swimming Pools, Spas, and Hot Tubs. Potable water supply to swimming pools, spas, and hot tubs shall be protected by an air gap or a reduced pressure principle backflow preventer in accordance with the following:

(1) The unit is equipped with a submerged fill line.

(2) The potable water supply is directly connected to the unit circulation system. 603.5.22 Chemical Dispensers. The water supply to chemical dispensers shall be protected against backflow by one of the following:
CPC § 2025 High relevance — show source text
An acceptable air supply for combustion and ventilation is necessary for the proper operation of fuel-burning appliances. A shortage of combustion air can result in incomplete combustion and the production of poisonous gases, such as carbon monoxide or appliance overheating. Ventilation air provides cooling for the appliance casing and internal controls. Inadequate ventilation of the space in which an appliance is installed can result in increased surrounding temperatures that stress the appliance itself or other appliances in the vicinity.

xiv 2025 CALIFORNIA PLUMBING CODE

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FORMAT OF THE UNIFORM PLUMBING CODE

Chapter 6 Water Supply and Distribution.

Chapter 6 regulates the design, material, and installation of water supply and distribution systems, including residential fire sprinklers. The water supply and distribution system is designed to achieve the correct water pressure and flow rates and avoid cross-connections. For fixtures to perform properly, an acceptable supply of potable water is essential to their operation and use. Cross-connections and backflow are ranked as the highest priority because of the long history of recognized health risks posed by cross-connections, outbreaks, or cases of waterborne disease. Piping materials and components are evaluated for their possible effect on the potable water with which they are in contact. The intent is to control the potential adverse health effects produced by indirect additives, products, and materials that come in contact with potable water. When selecting materials for water supply and distribution systems, consider water pressure, water temperature, compatibility with the water supply, durability, support, and sustainability.

In addition, this chapter regulates the design, location, materials, and installation of multipurpose and stand-alone sprinkler systems that do not include the use of antifreeze. Where systems are installed as a portion of the water distribution system under the requirements of this chapter and are not provided with a fire department connection, backflow protection for the water supply system is not required.

Chapter 7 Sanitary Drainage.

This chapter regulates the design and installation of sanitary drainage systems to ensure they will work as intended. Drainage piping should not be oversized nor undersized, and constructed of approved materials to guard against fouling, deposit of solids, clogging, and with cleanouts so arranged that the pipes may be readily cleaned. The purpose of the sanitary drainage system is to remove effluent discharged from plumbing fixtures and other equipment to an approved point of disposal, such as a public sanitary system or private sewage disposal system.

The basics of a sanitary drainage system include public and private sewage disposal; selection of materials; installation of the building drain and sewer; joining methods for pipe and fittings; drainage fixture units for sizing the drainage system; sumps and ejectors; vent sizing and length of vents; and testing.

Chapter 8 Indirect Wastes.

Chapter 8 regulates indirect waste connections that are required for plumbing fixtures and plumbing appliances dealing with food preparation, dishwashing, potable liquids, and similar equipment. An indirect connection prevents sewage from backing up into a fixture or appliance, thus providing protection against potential health hazards. The waste pipe discharges through an air gap or air break into a waste receptor or standpipe. The protection in the form of an air gap is necessary when the contamination is a potential health hazard or cross connection with the potable water system. Where there is no possibility of contaminating the potable water (nonpotable discharge), the indirect waste pipe may connect in the form of an air break.
CPC § 603.5.17 High relevance — show source text
603.5.17 Potable Water Outlets and Valves. Potable water outlets, freeze-proof yard hydrants, combination stop-and-waste valves, or other fixtures that incorporate a stop and waste feature that drains into the ground shall not be installed underground. 603.5.18 Pure Water Process Systems. The water supply to a pure water process system, such as dialysis water systems, semiconductor washing systems, and similar process piping systems, shall be protected from backpressure and backsiphonage by a reduced-pressure principle backflow preventer. 603.5.18.1 Dialysis Water Systems. The individual connections of the dialysis related equipment to the dialysis pure water system shall not require additional backflow protection. 603.5.19 Garbage Can Washers. Where garbage can washers are connected to a potable water supply system, the connection shall be protected against backflow in accordance with Table 603.2.

603.5.20 Plumbing Fixture Fittings. Plumbing fixture fittings with integral backflow protection shall comply with ASME A112.18.1/CSA B125.1. 603.5.21 Swimming Pools, Spas, and Hot Tubs. Potable water supply to swimming pools, spas, and hot tubs shall be protected by an air gap or a reduced pressure principle backflow preventer in accordance with the following:

(1) The unit is equipped with a submerged fill line.

(2) The potable water supply is directly connected to the unit circulation system. 603.5.22 Chemical Dispensers. The water supply to chemical dispensers shall be protected against backflow by one of the following:

(1) The chemical dispenser shall comply with ANSI/CAN/ASSE/IAPMO 1055. Where an installation involves a water source coming from a faucet with an integrated vacuum breaker device, a pressure bleed device conforming to IAPMO PS 104 shall be used to protect the vacuum breaker device.

(2) Water supply shall be protected by one of the following methods:

(a) Air gap

(b) Atmospheric vacuum breaker (AVB)

(c) Pressure vacuum breaker backflow prevention assembly (PVB)

(d) Spill-resistant pressure vacuum breaker (SVB)

(e) Reduced-pressure principle backflow prevention assembly (RP)

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2025 CALIFORNIA PLUMBING CODE 145

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WATER SUPPLY AND DISTRIBUTION

604.0 Materials.

604.1 Pipe, Tube, and Fittings. Pipe, tube, fittings, solvent cement, thread sealants, solders, and flux used in potable water systems intended to supply drinking water shall comply with NSF/ANSI/CAN 61. Where pipe fittings and valves are made from copper alloys containing more than 15 percent zinc by weight and are used in plastic piping systems, they shall be resistant to dezincification and stress corrosion cracking in compliance with NSF/ANSI 14.

Materials used in the water supply system, except valves and similar devices, shall be of a like material, except where otherwise approved by the Authority Having Jurisdiction.

Materials for building water piping and building supply piping shall comply with the applicable standards referenced in Table 604.1.
CPC § 103.3 Medium relevance — show source text
R 103.3 Water Heaters. Water heaters shall be installed in accordance with Chapter 5 and the manufacturer’s recommendations and instructions.

R 103.4 Potable Water Sources. Where a public water supply system is available, it shall be used. Private or alternate water sources shall comply with the potable water standards of the state, and local health authority. R 103.5 Water Supply to Fixtures. Each plumbing fixture shall be provided with an adequate supply of potable water in accordance with Chapter 6.

R 103.6 Protection of Potable Water. The potable water supply shall be protected from pollution and contamination in accordance with Section 602.0 and Section 603.0. Backflow prevention shall be in accordance with Table 603.2.

R 103.7 Water-Treatment Equipment. Where installed, water-treatment equipment shall comply with the requirements of Section 611.0.

R 103.8 Testing. Installations of water supply, drainage, and venting systems shall be tested and inspected in accordance with the requirements of this code.

R 201.0 Tiny House Fixtures.

R 201.1 Fixtures. Plumbing fixtures shall comply with the requirements of Chapter 4.

R 201.2 Kitchen. Each tiny house shall be provided with a kitchen sink.

R 201.3 Bathroom. Each tiny house shall be provided with not less than one water closet, one lavatory, and one bath, shower or combination bath/shower.

R 201.4 Bathtubs and Whirlpool Bathtubs. Where installed, bathtubs and whirlpool bathtubs shall be in accordance with Section 409.0.

R 201.5 Showers Compartments. Where installed, shower compartment enclosures shall be not less than 30 inches (762 mm) wide by 30 inches (762 mm) long.

R 201.6 Water Closet. Water closets shall be in accordance

with Section 411.0.

R 201.7 Lavatories. Lavatories shall be in accordance with

Section 407.0.

R 202.0 Tiny House Water Supply System. R 202.1 Water Service Outlet. Each tiny house shall be provided with a water service outlet delivering potable water. The water service outlet riser shall be not less than ¾ of an inch (20 mm) nominal pipe size. R 202.2 Sizing Water Supply and Distribution Sys- tems. Water distribution systems shall be sized in accordance with Section 610.0. Water supply piping, joints, and connections shall be installed in accordance with Chapter 6. R 202.3 Pressure. Each tiny house water distribution system shall be so designed and maintained at not less than 15 pounds force per square inch (psi) (103 kPa) at each fixture inlet in accordance with Section 608.1. Water pressure exceeding 80 psi (552 kPa), shall be limited in accordance with Section 608.2.

R 203.0 Tiny House Drain, Waste, and Vent (DWV) System. R 203.1 General. Sanitary drain, waste, and vent (DWV) systems shall be installed in accordance with Chapter 7 and Chapter 9. The DWV system shall connect to the public sanitary waste system. Private sewage disposal systems shall be permitted where approved by the Authority Having Jurisdiction. See Appendix H for private sewage disposal system general guidelines.
CPC § 302.2 Medium relevance — show source text
E 302.2 Water Service Outlet. Each manufactured home lot shall be provided with a water service outlet delivering potable water. The water service outlet riser shall be not less than [3] ⁄ 4 of an inch (20 mm) nominal pipe size and capable of delivering 12 water supply fixture units.

E 302.2.1 Connection. A manufactured home shall be connected to the park water service outlet by a flexible connector, such as copper or copper alloy or other approved material not less than [3] ⁄ 4 of an inch nominal (20 mm) interior diameter.

E 302.2.2 Water Supply Fixture Units. Park water distribution systems shall be designed to deliver a minimum of 12 water supply fixture units to each lot and installed with materials in accordance with Chapter 6, Appendix A, or both of this code.

E 302.2.3 Pressure. Each manufactured home park water distribution system shall be so designed and maintained as to provide a pressure of not less than 20 poundsforce per square inch (psi) (138 kPa) at each manufactured home lot at maximum operating conditions.

E 302.2.4 Location. Each lot water service outlet shall be located in the third rear section and within 4 feet (1219 mm) of the proposed location of the manufactured home.

E 302.3 Shutoff Valve. A separate water shutoff valve shall be installed in each water service outlet at each manufactured home lot. Where a listed backflow protective device is installed, the service shutoff shall be located on the supply side of such device.

E 302.4 Backflow Preventer. Where a condition exists in the plumbing of a manufactured home that creates a crossconnection, a listed backflow preventer shall be installed in the water service line to the manufactured home at or near the

water service outlet. Where a hose bibb or outlet is installed on the supply outlet riser in addition to the service connector, a listed backflow preventer shall be installed on each additional outlet.

E 302.5 Pressure-Relief Valve. Where it is required to install a backflow preventer at the manufactured home lot service outlet, a listed pressure-relief valve shall be installed in the water service line on the discharge side of the backflow preventer. Pressure-relief valves shall be set to release at a pressure at a maximum of 150 psi (1034 kPa). Pressurerelief valves shall discharge toward the ground. Backflow preventers and pressure-relief valves shall be not less than 12 inches (305 mm) above the ground.

408 2025 CALIFORNIA PLUMBING CODE

), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

APPENDIX E

E 302.6 Mechanical Protection. Park water service out lets, backflow preventers, and pressure-relief valves shall be protected from damage by vehicles or other causes. Such protection shall be permitted to consist of posts, fencing, or other permanent barriers.

E 302.7 Water-Conditioning Equipment. A permit shall be obtained from the Authority Having Jurisdiction before installing water-conditioning equipment on a manufactured home lot. Approval of the park operator is required on applications for a permit to install such equipment. Where the water-conditioning equipment is of the regenerating type, and the park drainage system discharges into a public sewer, approval of the sanitary district or agency having jurisdiction over the public sewer is required.

CPC § 3-2020 Medium relevance — show source text

2025 CALIFORNIA PLUMBING CODE 337

REFERENCED STANDARDS

TABLE 1701.1 (continued) REFERENCED STANDARDS

STANDARD NUMBER	STANDARD TITLE	APPLICATION	REFERENCED SECTION
ASSE 1012-2009	Backflow Preventers with an Intermediate Atmospheric Vent	Backflow Protection	Table 603.2
ASSE 1013-2021	Reduced Pressure Principle Backflow Prevention Assemblies	Backflow Protection	Table 603.2
ASSE 1014-2020	Backflow Prevention Devices for Hand-Held Showers	Backflow Protection	417.3
ASSE 1015-2021	Double Check Backflow Prevention	Backflow Protection	Table 603.2
ASSE 1016-2017/ASME A112.1016-2017/CSA B125.

CPC § 1303.4.2 Medium relevance — show source text
steamer.

1303.4.2 Vapor Vents and Stacks. Where a sterilizer or bedpan steamer has provision for a vapor vent and such a vent is required by the manufacturer, the vent shall be extended to the outdoors above the roof. Sterilizer and bedpan steamer vapor vents shall be installed in accordance with the manufacturer’s installation instructions and shall not be connected to a drainage system vent.

1303.5 Aspirators. Provisions for aspirators or other watersupplied suction devices shall be installed with the specific approval of the Authority Having Jurisdiction. Where aspirators are used for removing body fluids, they shall include a collection container to collect liquids and solid particles. Aspirators shall indirectly discharge to the sanitary drainage system through an air gap in accordance with Section 806.1. The potable water supply to an aspirator shall be protected by a vacuum breaker or equivalent backflow protection device in accordance with Section 603.5.9.

1303.6 Drains. Drains shall be installed on dryers, aftercoolers, separators, and receivers.

1303.7 Clinical Sinks. Clinical sinks shall be installed in

accordance with the manufacturer’s installation instructions

and shall comply with Section 1303.7.1.

1303.7.1 Drainage Connection. Clinical sinks shall be directly connected to the sanitary drainage system and shall be provided with approved flushing devices installed in accordance with Section 413.1.

1303.8 Water Supply for Hospitals. Hospitals shall be provided with not less than two approved potable water sources that are installed in such a manner as to prevent the interruption of water service.

1303.9 Work Performed in Occupied Healthcare Facilities. In existing, occupied, inpatient healthcare facilities, all plumbing systems installation and remodel work shall be performed by personnel certified in accordance with ASSE/IAPMO/ANSI 12010.

1304.0 Medical Gas and Medical Vacuum Piping Sys- tems.

1304.1 General. The installation of medical gas and medical vacuum piping systems shall comply with the requirements of this chapter. 1304.1.1 [OSHPD 1, 1R, 2, 3, 4 & 5] Medical gas sys- tems for health care facilities that are regulated by OSHPD (hospitals, skilled nursing facilities, and intermediate care facilities, licensed clinics, and correctional treatment cen- ters) shall be in accordance with NFPA 99, Standard for Health Care Facilities. See California Fire Code Refer- enced Standards (Chapter 80) for applicable version of the Standard. See California Building Code Table 1224.4.6.1 for location and number of station outlets for oxygen, vac- uum, and medical air.
CPC § 1502.3.3 Medium relevance — show source text
(3) The drain on the alternate water source system shall be checked for flow during the test and fixtures, potable and alternate water source, shall be tested and inspected for flow. Flow from an alternate water source system outlet indicates a cross-connection. No flow from a potable water outlet shall indicate that it is connected to the alternate water source sys tem.

(4) The potable water system shall then be depressurized and drained.

(5) The alternate water source system shall then be activated and pressurized. When an alternate water source is not available for the initial cross-connec- tion test, a temporary connection to a potable water supply shall be required. At the conclusion of the ini- tial cross-connection test, the temporary connection to the potable water supply shall be disconnected.

(6) The alternate water source system shall remain pressurized for a minimum period specified by the Authority Having Jurisdiction while the potable water system is empty. The minimum period the potable water system is to remain depressurized shall be determined on a case-by-case basis, but in no case shall that period be less than 1 hour.

(7) Fixtures, potable, and alternate water source shall be tested and inspected for flow. Flow from a potable water system outlet indicates a cross-connection. No flow from an alternate water source outlet will indicate that it is connected to the potable water system.

(8) The drain on the potable water system shall be checked for flow during the test and at the end of the

test.

(9) Where there is no flow detected in the fixtures which would indicate a cross-connection, the potable water system shall be repressurized. 1502.3.3 Discovery of Cross-Connection. If a cross-connection is discovered, the following procedure, in the presence of the Authority Having Jurisdiction, shall be activated immediately:

(1) Notify the Authority Having Jurisdiction of the cross connection.

( 2 ) The alternate water source piping to the building and its premises shall be shutdown at the meter, and the alternate water source riser shall be drained.

( 3 ) Potable water piping to the building and its prem- ises shall be shutdown at the meter.

( 4 ) The cross-connection shall be uncovered and disconnected.

( 5 ) The building and its premises shall be retested in accordance with Section 1502.3.1 and Section

1502.3.2.

( 6 ) The potable water system shall be chlorinated with 50 parts-per-million (ppm) chlorine for 24 hours.

( 7 ) The potable water system shall be flushed after 24 hours, and a standard bacteriological test shall be performed. Where test results are acceptable, the potable water system shall be permitted to be recharged. 1502.4 Separation Requirements. Underground alternate water source service piping other than gray water shall be separated from the building sewer in accordance with this code. Pipes carrying treated nonpotable water shall be permitted to be run or laid in the same trench as potable water pipes with a 12 inch (305 mm) minimum vertical and horizontal separation where both pipe materials are approved for use within a building. Where horizontal piping materials do not comply with this requirement, the minimum separation shall be increased to 60 inches (1524 mm). The potable water piping shall be installed at an elevation above the treated nonpotable water piping.

CPC § 603.2 Medium relevance — show source text

2025 CALIFORNIA PLUMBING CODE 337

REFERENCED STANDARDS

TABLE 1701.1 (continued) REFERENCED STANDARDS

STANDARD NUMBER	STANDARD TITLE	APPLICATION	REFERENCED SECTION
ASSE 1012-2009	Backflow Preventers with an Intermediate Atmospheric Vent	Backflow Protection	Table 603.2
ASSE 1013-2021	Reduced Pressure Principle Backflow Prevention Assemblies	Backflow Protection	Table 603.2
ASSE 1014-2020	Backflow Prevention Devices for Hand-Held Showers	Backflow Protection	417.3
ASSE 1015-2021	Double Check Backflow Prevention	Backflow Protection	Table 603.2
ASSE 1016-2017/ASME A112.1016-2017/CSA B125.16-2017	Automatic Compensating Valves for Individual Showers and Tub/Shower Combinations	Valves	408.4, 408.4.2(1)
ASSE 1018-2001 (R2021)	Trap Seal Primer Valves - Potable Water Supplied	Valves	1007.2
ASSE 1019-2011 (R2016)	Wall Hydrant with Backflow Protection and Freeze Resistance	Backflow Protection	Table 603.2
ASSE 1020-2020	Pressure Vacuum Breaker Assemblies	Backflow Protection	Table 603.2
ASSE 1022-2021	Backflow Preventer for Beverage Dispensing Equipment	Backflow Protection	Table 603.2, 603.5.12
ASSE 1023-2020	Electrically Heated or Cooled Water Dispensers	Appliances	417.6
ASSE 1024-2017 (R2021)	Dual Check Backflow Preventers	Backflow Protection	Table 603.2, 603.5.12
ASSE 1032-2004 (R2021)	Dual Check Valve Type Backflow Preventers for Carbonated Beverage Dispensers, Post Mix Type	Backflow Protection	603.5.12
ASSE 1035-2020	Laboratory Faucet Backflow Preventers	Backflow Protection	Table 603.2, 603.3.11
ASSE 1037-2020/ASME A112.1037-2020/CSA B125.37-2020	Pressurized Flushing Devices for Plumbing Fixtures	Backflow Protection	413.2
ASSE 1044-2015 (R2020)	Trap Seal Primer - Drainage Types and Electric Design Types	DWV Components	1007.

CPC § 3.5.2 High relevance — show source text
pump.

R309.3.5.2 Required capacity. The water supply shall have the capacity to provide the required design flow rate for sprinklers for a period of time as follows:
1. Seven minutes for dwelling units one story in height and less than 2,000 square feet (186 m [2] ) in area. For the purpose of determining the area of the dwelling unit, the area of attached garages and attached open carports, porches, balconies and patios shall not be included.
2. Ten minutes for dwelling units two or more stories in height or equal to or greater than 2,000 square feet (186 m [2] ) in area. For the purpose of determining the area of the dwelling unit, the area of attached garages and attached open carports, porches, balconies and patios shall not be included.
R309.3.5.2.1 Where a well system, a water supply tank system or a combination thereof is used, the configuration for the system shall be one of the following: 1. The water supply shall serve both domestic and fire sprinkler systems. Any combination of well capacity and tank storage shall be permitted to meet the capacity requirement. 2. A stand-alone tank is permitted if the following conditions are met: 2.1. The pump shall be connected to a 220-volt circuit breaker shared with a common household appliance (e.g., range, oven, dryer), 2.2. The pump shall be a stainless steel 240-volt pump, 2.3. A valve shall be provided to exercise the pump. The discharge of the exercise valve shall be piped to the tank, and

2.4. A sign shall be provided stating “Valve must be opened monthly for 5 minutes.” 2.5. A means for automatically refilling the tank level so that the tank capacity will meet the required water supply duration in minutes shall be provided.

R309.3.5.3 Connections to automatic fire sprinkler systems. The potable water supply to automatic fire sprinkler shall be protected against backflow by a double check backflow prevention assembly, a double check fire protection backflow prevention assembly, a reduced pressure principle backflow prevention assembly or a reduced pressure principle fire protection backflow prevention assembly.

Exception: Where permitted by Section R309.3.1.1, backflow protection for the water supply system shall not be required.

R309.3.5.3.1 Additives or nonpotable source. Where systems contain chemical additives or antifreeze, or where systems are connected to a nonpotable secondary water supply, the potable water supply shall be protected against backflow by a reduced pressure principle backflow prevention assembly or a reduced pressure principle fire protection backflow prevention assembly. Where chemical additives or antifreeze is added to only a portion of an automatic sprinkler or standpipe system, the reduced pressure principle fire protection backflow preventer shall be permitted to be located so as to isolate that portion of the system.

R309.3.6 Pipe sizing. The piping to sprinklers shall be sized for the flow required by Section R309.3.4.2. The flow required to supply the plumbing fixtures shall not be required to be added to the sprinkler design flow.
CPC § 102.3 Medium relevance — show source text
P 102.3 Service Plumber Technician. Professional qualification for plumbing service technicians shall be qualified to ASSE/IAPMO/ANSI Series 13000.

P 102.3.1 Qualification for Service Plumbers. Professional qualification for service plumbers shall be in accordance ASSE/IAPMO/ANSI 13010.

P 102.4 Cross-Connection Control. Professional qualification for cross-connection control professionals shall be in accordance with ASSE/IAPMO/ANSI Series 5000.

P 102.4.1 Qualification for Backflow Testers. Professional qualification for backflow assembly testers shall be in accordance with ASSE/IAPMO/ANSI 5110.

P 102.4.2 Qualification for Surveyors. Professional qualification for cross-connection assembly surveyors shall be qualified in accordance with ASSE/IAPMO/ANSI 5120.

P 102.4.3 Qualification for Repairers. Professional qualification for backflow prevention assembly repairers shall be in accordance with ASSE/IAPMO/ANSI 5130.

P 102.4.4 Qualification for Fire Protection Sys- tems. Professional qualification for backflow assembly testers of fire protection systems shall be in accordance with ASSE/IAPMO/ANSI 5140.

P 102.4.5 Qualification for Program Administrator. Professional qualification for backflow prevention administrator shall be in accordance with ASSE/IAPMO/ANSI
P 102.5 Medical Gas Systems. Professional qualification for medical gas systems personnel shall be in accordance with ASSE/IAPMO/ANSI Series 6000.

P 102.5.1 Qualification for Medical Gas Installers. Professional qualification for medical gas system installers shall be in accordance with ASSE/IAPMO/ANSI 6010.

P 102.5.2 Qualification for Bulk Medical Gas/Cryo- genic Fluid Installers. Professional qualification for bulk medical gas/cryogenic fluid installers shall be in accordance ASSE/IAPMO/ANSI 6015.

P 102.5.3 Qualification for Medical Gas Systems Inspectors. Professional qualification for medical gas systems inspectors shall be in accordance with ASSE/IAPMO/ANSI 6020.

P 102.5.4 Qualification for Medical Gas System Verifiers. Professional qualification for medical gas system verifiers shall be in accordance with ASSE/IAPMO/ANSI 6030.

P 102.5.5 Qualification for Bulk Medical Gas/Cryo- genic Fluid Central Supply System Verifiers. Professional qualification for bulk medical gas/cryogenic fluid central supply system verifiers shall be in accordance with ASSE/IAPMO/ANSI 6035.

P 102.5.6 Qualification for Medical Gas Systems Maintenance. Professional qualification for medical gas systems maintenance personnel shall be in accordance with ASSE/IAPMO/ANSI 6040.

P 102.6 Residential Potable Water Fire Sprinkler Sys- tem Installers and Inspectors for One- and Two-Fam- ily Dwellings. Professional qualification for residential potable water fire protection system installers and inspectors for one- and two-family dwellings shall be in accordance with ASSE/IAPMO/ANSI Series 7000.
CPC § 603.5.12 Medium relevance — show source text
603.5.12 Beverage Dispensers. Potable water supply to carbonated beverage dispensers shall be protected by an air gap or a vented backflow preventer that complies with ASSE 1022. For carbonated beverage dispensers, piping material installed downstream of the backflow preventer shall not be affected by carbon dioxide gas. Non-carbonated beverage dispensers, such as ice makers and coffee machines, shall be protected by an air gap or dual check backflow preventer that comply with ASSE 1032 or ASSE 1024.

603.5.13 Deck-Mounted and Equipment- Mounted Vacuum Breakers. Deck-mounted or equipment-mounted vacuum breakers shall be installed in accordance with their listing and the manufacturer’s installation instructions, with the critical level not less than 1 inch (25.4 mm) above the flood-level rim.

603.5.14 Protection from Fire Systems.

Note: Fire Protection Systems has not been adopted by the State Fire Marshal. This section cannot be adopted or enforced pursuant to California Health and Safety Code 13114.7(a), which is being cited for reference. California Health and Safety Code 13114.7.

(a) For the purposes of this section the following are definitions of class I and class II systems:

144 2025 CALIFORNIA PLUMBING CODE

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WATER SUPPLY AND DISTRIBUTION

(1) American Water Works Association [A.W.W.A] Manual No. M-14 class 1 – Automatic fire sprinkler systems with direct connection from public water mains only; no pumps, tanks, or reservoirs; no physical connection from other water supplies; no antifreeze or additives of any kind; and all sprinkler drains discharging to the atmosphere or other safe outlets.

(2) American Water Works Association [A.W.W.A] Manual No. M-14 class 2 – Automatic fire sprinkler systems which are the same as class 1, except that booster pumps may be installed in the connections from the street mains.

(b) Automatic fire sprinkler systems described in subdi- vision (a) shall not require any backflow protection equipment at the service connection other than required by standards for those systems contained in the publication of the National Fire Protection Association entitled “Installation of Sprinkler Sys- tems” [NFPA Pamphlet No. 13, 1980 edition]. 603.5.14.1 Fire Department Connection. Where fire protection systems supplied from a potable water system include a fire department (siamese) connection that is located less than 1700 feet (518.2 m) from a nonpotable water source that is capable of being used by the fire department as a secondary water supply, the potable water supply shall be protected by one of the following:

(1) Reduced pressure principle backflow prevention assembly (RP)

(2) Reduced pressure detector fire protection backflow prevention assembly
California Plumbing Code Medium relevance — show source text
; 2′ C.R.S. with 1″ cover on
both top and bottom flanges; 13′1″ span
restrained.|60 psf|2 hrs|||7|1, 3|2| |F/C-6-RC-34|61/4″|61/4″ thick; 43/4″ (5120 psi) concrete core;
1″ T&G board flooring;1/2″ plaster under-
coat; 4″ × 3″ × 10 lbs R.S.J.; 3′ C.R.S. flush
with top surface concrete; 12′ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|100 psf|4 hrs|||7|1, 7|4| |F/C-6-RC-35|61/4″|43/4″ (3600 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat; 4″ ×
3″ × 10 lbs R.S.J.; 3′ C.R.S. flush with top
surface concrete; 12′ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|100 psf|2 hrs
30 min|||7|1, 5|21/2| |F/C-6-RC-36|61/4″|43/4″ (2800 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat; 4″ ×
3″ × 10 lbs R.S.J.; 3′ C.R.S. flush with top
surface concrete; 12″ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|80 psf|4 hrs|||7|1, 7|4| |F/C-7-RC-37|7″|(3640 psi) concrete deck;1/4″ reinforce-
ment bars at 6″ pitch with 11/2″ cover;1/4″
reinforcement bars at 5″ pitch perpendic-
ular with 11/2″ cover; 13′1″ span
restrained.|169 psf|6 hrs|||7|1, 14|6| |F/C-7-RC-38|7″|(4060 psi) concrete deck; 4″ × 3″ × 10 lbs
R.S.J.; 2′6″ C.R.S. with 11/2″ cover on both
top and bottom flanges; 4″ × 6″ × 13 SWG
mesh reinforcement 11/2″ from bottom of
slab; 13′1″ span restrained.|175 psf|6 hrs|||7|1, 14|6| |F/C-7-RC-39|71/4″|53/4″ (4010 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat;
4″ × 3″ × 10 lbs R.S.J.; 2′6″ C.R.S.

CPC § 9.1 Medium relevance — show source text

SHUTOFF VALVE APPLICATION	STANDARDS
Appliance shutoff valve up to1_/_2 psi	CSA/ANSI Z21.15/CSA 9.1
Appliance shutoff valve up to1_/_2 psi	ASME B16.44
Appliance shutoff valve up to1_/_2 psi	ASME B16.33 marked 125 G
Appliance shutoff valve up to1_/_2 psi	CSA/ANSI LC 4/CSA 6.32
Valve up to1_/_2 psi	ASME B16.44
Valve up to1_/_2 psi	ASME B16.33 marked 125 G
Valve up to1_/_2 psi	CSA/ANSI LC 4/CSA 6.32
Valve up to 2 psi	ASME B16.44 labeled 2G
Valve up to 2 psi	ASME B16.33 marked 125 G
Valve up to 2 psi	CSA/ANSI LC 4/CSA 6.32 with ANSI/ASME B16.44 labeled 2G or labeled 5G
Valve up to 2 psi	CSA/ANSI LC 4/CSA 6.32 with ANSI/ASME B16.33 marked 125 G
Valve up to 5 psi	ASME B16.44 labeled 5G
Valve up to 5 psi	ASME B16.33
Valve up to 5 psi	CSA/ANSI LC 4/CSA 6.32 with ANSI/ASME B16.44 marked 5G
Valve up to 5 psi	CSA/ANSI LC 4/CSA 6.32 with ANSI/ASME B16.33 marked 125 G
Valve up to 125 psi	ASME B16.33 marked 125 G
Valve up to 125 psi	CSA/ANSI LC 4/CSA 6.32 with ASME B16.33 marked 125 G

For SI Units: 1 pound-force per square inch = 6.8947 kPa

1308.13 Expansion and Flexibility. Piping systems shall be designed to prevent failure from thermal expansion or contraction. [NFPA 54:5.13.1]

CPC § 08-15 Medium relevance — show source text
6” x 6” x 8’-0” Long, Cylindrical Post, 6” in Diameter x 8’-0” Long, Fully Treated
(see Note 4 on Page 1)| |3|Conduit (load side), Size and Material as Required by Building Code
(typically rigid galvanized steel or Schedule 80 PVC plastic)| |4|Conduit, Service Riser, Rigid Steel, Galvanized or Schedule 80 PVC Plastic, (see Note 5 on Page 3)| |5|Conduit, Rigid Steel, Galvanized, With Pipe Strap (for bare ground wire, omit if armor clad wire is used)| |6|Hub and Clamp, Grounding, to Suit Item 5| |7|Ground Rod (see Note 6)| |8|Ground Wire, Copper, Bare or Armor Clad
(size in accordance with applicable electrical codes and local requirements)| |9|Conduit, Plastic or Rigid Steel, for Underground Service (size as shown inDocument 063927
andDocument 063928)|

054712 Page 2 of 4 Rev. #09: 08-15-17

UG-1: Services Greenbook Permanent Wood Post Installation Underground Electric Service EMWP

Residential Service Only, 0−225 Amp

Notes
1. Poured concrete pad shall be approximately 4 inches thick. Provide 1/2-inch slope away from post to allow for drainage.
2. Install bend in direction of service trench. To facilitate cable installation, only one 90 ° bend is permitted in the service riser installation. If trench is shared with gas or other utilities, consult PG&E for required increased trench depth.
3. Meter socket enclosures for residential service (Figure 2) shall not be equipped with any circuit closing device.
4. Approved meter socket enclosures for non-residential service (Figure 4 on Page 4) shall be equipped with test bypass facilities.
5. Whenever it is necessary to install a service longer than 75 feet, the applicant must contact PG&E before ordering the service riser, conduit or, termination facilities. If the service riser and conduit called for in Table 2 on Page 4 will not accept the cable required to meet the voltage and/or flicker drop requirements, or will cause cable pulling problems, the next larger PG&E standard conduit size must be installed. (Refer to Document 041543 for flicker and voltage drop requirements and Document 038193 for cable pulling limitations.)
66” Preferred

CPC § 08-15 Medium relevance — show source text

Notes

Poured concrete pad shall be approximately 4 inches thick. Provide 1/2-inch slope away from post to allow for drainage.
Install bend in direction of service trench. To facilitate cable installation, only one 90 ° bend is permitted in the service riser installation. If trench is shared with gas or other utilities, consult PG&E for required increased trench depth.
Meter socket enclosures for residential service (Figure 2) shall not be equipped with any circuit closing device.
Approved meter socket enclosures for non-residential service (Figure 4 on Page 4) shall be equipped with test bypass facilities.
Whenever it is necessary to install a service longer than 75 feet, the applicant must contact PG&E before ordering the service riser, conduit or, termination facilities. If the service riser and conduit called for in Table 2 on Page 4 will not accept the cable required to meet the voltage and/or flicker drop requirements, or will cause cable pulling problems, the next larger PG&E standard conduit size must be installed. (Refer to Document 041543 for flicker and voltage drop requirements and Document 038193 for cable pulling limitations.)

66” Preferred

1 Customer’s N d Distribution Section 8” Min. −125 Amp. 11” Min. 6−225 Amp. Sealable Cover	Col2	Col3	Col4
8” Min. −125 Amp. 11” Min. 6−225 Amp. N Sealable Cover Customer’s Distribution Section d 1			Customer’s Distribution Section
8” Min. −125 Amp. 11” Min. 6−225 Amp. N Sealable Cover Customer’s Distribution Section d 1	N
8” Min. −125 Amp. 11” Min. 6−225 Amp. N Sealable Cover Customer’s Distribution Section d 1	N	Sealable Cover	Sealable Cover

Figure 2 Typical Residential Combination Service Termination Enclosure and Meter Socket Panel, 225 Amp Max., 120/240 V

Figure 1 Residential Service

Rev. #09: 08-15-17 054712 Page 3 of 4

UG-1: Services Greenbook Permanent Wood Post Installation Underground Electric Service EMWP

Residential and Non-Residential Service 0−225 Amp Installed in Conduit

66” Preferred

To Load

Frequently asked questions

Do I always need a reduced‑pressure (RP) device on a potable service?

Not always. An RP is required where the hazard is high (health hazard, chemical injection) or where backpressure can occur (e.g., pumps, booster connections). For lower‑hazard, non‑backpressure situations the code allows vacuum breakers, dual checks or other listed devices per the specific subsection (see § 603.5.6, § 603.5.5) .

Can I install a backflow preventer underground or in a meter pit?

Generally no — the CPC and the appended guidance require devices and relief valves to be accessible and not installed where they cannot be serviced. Some specific outlets are not to be installed underground; see § 603.5.17 and E 302 provisions for mounting and clearance details file.

Who can test or repair backflow assemblies?

The CPC references professional qualification standards for testers, repairers, and program administrators (P 102 series and ASSE/IAPMO standards). Use certified backflow testers and repairers as required by the AHJ § P 102.4 – P 102.4.4 (referenced in the CPC excerpts) .

If I add an RP to an existing fire sprinkler connection, do I need to recalculate hydraulics?

Yes. The code requires that when a backflow device is installed on a potable supply to a fire protection system, the hydraulic design must account for the pressure drop through the device and be verified for sufficient sprinkler performance (§ 603.5.14.3) .

Is an air gap always the preferred protection method?

An air gap is the most fail‑safe method because it physically separates the potable supply; where practicable and code‑allowed it is acceptable. Where an air gap is impractical or not permitted by the fitting/installation, listed backflow assemblies (vacuum breakers, PVB, RP, etc.) are used per the applicable CPC subsection (see § 603.5.5 and Table 603.2) file.

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Related in the CPC

How do I select the correct backflow prevention device for a given hazard?

What backflow protection is required for fire-protection systems and fire-department connections?

Cross-Connections and Backflow Protection

California Plumbing Code