CPC · California Plumbing Code

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

If a potable-water‑fed sprinkler or standpipe has a fire-department connection within 1700 ft of a nonpotable source (or the system contains antifreeze/chemicals), the California Plumbing Code requires protection of the potable supply with a reduced‑pressure backflow assembly (or a reduced‑pressure detector type) and requires the system hydraulics be checked to account for the device’s pressure loss.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

The California Plumbing Code requires that where a potable water–supplied fire-protection system has a fire department (siamese) connection located less than 1700 feet (518.2 m) from a nonpotable water source, the potable supply must be protected by a reduced-pressure principle backflow prevention assembly (RP) or a reduced pressure detector fire protection backflow prevention assembly — § 603.5.14.1. The same two device choices are required when antifreeze, corrosion inhibitors, or other chemicals are added to a fire-protection system — § 603.5.14.2. When a backflow device is installed the hydraulic design of the sprinkler/standpipe system must account for the pressure drop through that device and retrofits must be checked to verify adequate operating pressure — § 603.5.14.3.

The single most important rule: if an FDC is within 1700 ft of any usable nonpotable source — or the system contains chemicals/antifreeze — protect the potable supply with an RP (or reduced-pressure detector) and verify system hydraulics.

Requirements in detail

Scope / status note

  • The CPC text includes a note that the Fire Protection Systems portion has not been adopted by the State Fire Marshal and therefore “this section cannot be adopted or enforced pursuant to California Health and Safety Code 13114.7(a).” That note appears in the CPC commentary where § 603.5.14 is located; be aware some enforcement or local applicability may be affected by that statutory relationship.

When RP / reduced-pressure detector is required

  • If a potable-water–supplied fire protection system includes a fire department connection (FDC) that is located less than 1700 feet (518.2 m) from a nonpotable water source that the fire department can use as a secondary supply, the potable system must be protected by one of:

    • Reduced pressure principle backflow prevention assembly (RP), or
    • Reduced pressure detector fire protection backflow prevention assembly (RPD / RP with detector).
      See § 603.5.14.1.

  • If antifreeze, corrosion inhibitors, or other chemicals are added anywhere in the fire-protection system supplied from a potable source, the potable system must be protected by one of the same two assemblies (RP or RPD). See § 603.5.14.2.

Hydraulic design and retrofit checks

  • Where a backflow device is installed on the potable supply to a fire-protection system, the system hydraulic design must explicitly account for the pressure drop through the backflow device. When devices are retrofitted the sprinkler hydraulics must be checked to verify sufficient water pressure will remain for satisfactory sprinkler operation. See § 603.5.14.3.

Key device definitions (where defined in Chapter 6)

  • Reduced-Pressure Principle Backflow Prevention Assembly (RP) — described in the CPC definitions for backflow assemblies (see § 603.3.7).
  • Reduced-Pressure Detector Fire Protection Backflow Prevention Assembly — a reduced-pressure assembly with a parallel detector assembly (meter + RP) (see § 603.3.9).

Decision table (quick reference)

Situation / trigger Required protection (options) Why it matters Code Reference
FDC located < 1700 ft (518.2 m) from a nonpotable source usable by fire department RP or Reduced-pressure detector fire protection assembly Prevents contamination when fire crews draft or use tankers/other nonpotable sources § 603.5.14.1
Antifreeze, corrosion inhibitors, or other chemicals added to system supplied from potable water RP or Reduced-pressure detector fire protection assembly Chemicals create a contamination hazard that RP devices must protect against § 603.5.14.2
Any installation of backflow device on potable supply to fire system (new or retrofit) Account for pressure drop in hydraulic calculations; verify adequate sprinkler pressure Ensures sprinklers/standpipes can still meet design flows/pressures after device is installed § 603.5.14.3

Exceptions & special cases

  • The CPC contains a specific note that the Fire Protection Systems section has not been adopted by the State Fire Marshal and therefore may be limited in enforceability pursuant to Health and Safety Code 13114.7(a) — check local authority adoption and enforcement before relying solely on this CPC text for enforcement interpretation.
  • The CPC text prescribes the required device type for the two triggers above but does not list device sizing, manufacturer loss coefficients, or installation details — those must be chosen per device listing, manufacturer data, and in coordination with the AHJ. See § 603.5.14.1–.3 and the device definitions in § 603.3.

Common mistakes

  • Assuming a double-check or dual-check device is acceptable when chemicals or a nearby nonpotable source are involved — the CPC requires RP (or RPD) in those cases (see § 603.5.14.1 and § 603.5.14.2).
  • Forgetting to verify that the hydraulic capacity remains sufficient after adding the backflow device — the code requires the hydraulic design to account for device pressure loss and retrofits to be re-checked (§ 603.5.14.3).
  • Not confirming local applicability: relying on the CPC text without checking the State Fire Marshal / local AHJ status for § 603.5.14 (see the adoption note).

Worked example

Scenario: An office building’s automatic wet-pipe sprinkler system is supplied from the potable domestic main. The building has a fire department connection (FDC) mounted at the street. A fire department tanker drafting point (a nonpotable source the fire department may use) is located 1,200 ft from the FDC.

  1. Trigger check: The FDC is less than 1,700 ft from a nonpotable source (1,200 ft < 1,700 ft) → code requires protection. See § 603.5.14.1.
  2. Device selection: Provide either a Reduced-Pressure Principle backflow assembly (RP) or a reduced pressure detector fire protection backflow assembly on the potable service feeding the sprinkler system, per § 603.5.14.1.
  3. Hydraulic check: Suppose the sprinkler design requires 60 psi at the riser for required flows, and the available supply (point of connection) before the backflow device is 75 psi. The CPC requires you to account for the pressure drop through the backflow device and confirm the riser still receives the required pressure — § 603.5.14.3. The CPC text does not specify the device pressure loss; you must use the manufacturer’s test data or measured loss for the selected RP/RPD and subtract that from supply pressure to confirm ≥ 60 psi at the riser. If the remaining pressure would be insufficient, hydraulics must be adjusted (e.g., larger supply, pump, or different arrangement) before approval.

Related provisions (CPC sections)

  • § 603.5.14 — Protection from fire systems (note and introductory language).
  • § 603.5.14.1 — Fire Department Connection (FDC) proximity rule and required device choices.
  • § 603.5.14.2 — Chemicals (antifreeze, corrosion inhibitors) trigger RP/RPD requirement.
  • § 603.5.14.3 — Hydraulic design must account for device pressure drop; retrofits must be checked.
  • § 603.3.7 — Definition / description of Reduced-Pressure Principle Backflow Prevention Assembly (RP).
  • § 603.3.9 — Definition / description of Reduced Pressure Detector Fire Protection Backflow Prevention Assembly (RP with detector).
  • § 603.4 — General requirements for assemblies (listing, AHJ acceptance, etc.).

Code references

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

  • 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 § 603.5.14.2 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 § 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 § 603.5.12 High 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

    ), 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

  • CPC § 912.5.4 High relevance — show source text

    912.5.4 Indication of pressure. The sign also shall indicate the pressure required at the outlets to deliver the standpipe system demand.

    Exception: Where the pressure required is 150 pounds per square inch (1034 kPa) or less.

    912.6 Backflow protection. The potable water supply to automatic sprinkler and standpipe systems shall be protected against backflow as required by the Health and Safety Code Section 13114.7.

    912.7 Inspection, testing and maintenance. Fire department connections shall be periodically inspected, tested and maintained in accordance with California Code of Regulations, Title 19, Division 1, Chapter 5 . Records of inspection, testing and maintenance shall be maintained.

    SECTION 913—FIRE PUMPS

    913.1 General. Where provided, fire pumps for fire protection systems shall be installed in accordance with this section and NFPA 20.

    Exception: Pumps for automatic sprinkler systems installed in accordance with Section 903.3.1.3, or Section P2904 of the Califor- nia Residential Code .

    913.2 Protection against interruption of service. The fire pump, driver and controller shall be protected in accordance with NFPA 20 against possible interruption of service through damage caused by explosion, fire, flood, earthquake, rodents, insects, windstorm, freezing, vandalism and other adverse conditions.

    913.2.1 Protection of fire pump rooms. Rooms where fire pumps are located shall be separated from all other areas of the building in accordance with Section 913.2.1 of the California Building Code .

    913.2.2 Circuits supplying fire pumps. Cables used for survivability of circuits supplying fire pumps shall be protected using one of the following methods:

    1. Cables used for survivability of required critical circuits shall be listed in accordance with UL 2196 and shall have a fireresistance rating of not less than 1 hour.
    2. Electrical circuit protective systems shall have a fire-resistance rating of not less than 1 hour. Electrical circuit protective systems shall be installed in accordance with their listing requirements.
    3. Construction having a fire-resistance rating of not less than 1 hour.
    4. The cable or raceway is encased in a minimum of 2 inches (51 mm) of concrete.

    Exception: This section shall not apply to cables, or portions of cables, located within a fire pump room or generator room that is separated from the remainder of the occupancy with fire-resistance-rated construction.

    913.3 Temperature of pump room. Suitable means shall be provided for maintaining the temperature of a pump room or pump house, where required, above 40°F (5°C).

    913.3.1 Engine manufacturer’s recommendation. Temperature of the pump room, pump house or area where engines are installed shall never be less than the minimum recommended by the engine manufacturer. The engine manufacturer’s recommendations for oil heaters shall be followed.

    913.4 Valve supervision. Where provided, the fire pump suction, discharge and bypass valves, and isolation valves on the backflow prevention device or assembly shall be supervised open by one of the following methods:

    1. Central-station, proprietary or remote-station signaling service.
    2. Local signaling service that will cause the sounding of an audible signal at a constantly attended location.
    3. Locking valves open.
    4. Sealing of valves and approved weekly recorded inspection where valves are located within fenced enclosures under the control of the owner.

    913.4.1 Test outlet valve supervision. Fire pump test outlet valves shall be supervised in the closed position.

  • 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 § 903.3.5 High relevance — show source text

    903.3.5 Water supplies. Water supplies for automatic sprinkler systems shall comply with this section and the standards referenced in Section 903.3.1. The potable water supply shall be protected against backflow in accordance with Health and Safety Code 13114.7 . For connections to public waterworks systems, the water supply test used for design of fire protection systems shall be adjusted to account for seasonal and daily pressure fluctuations based on information from the water supply authority and as approved by the fire code official.

    903.3.5.1 Domestic services. Where the domestic service provides the water supply for the automatic sprinkler system, the supply shall be in accordance with this section.

    903.3.5.2 Residential combination services. A single combination water supply shall be allowed provided that the domestic demand is added to the sprinkler demand as required by NFPA 13R.

    903.3.6 Hose threads. Fire hose threads and fittings used in connection with automatic sprinkler systems shall be as prescribed by the fire code official.

    903.3.7 Fire department connections. Fire department connections for automatic sprinkler systems shall be installed in accordance with Section 912.

    903.3.8 Limited area sprinkler systems. Limited area sprinkler systems shall be in accordance with the standards listed in Section 903.3.1 except as provided in Sections 903.3.8.1 through 903.3.8.5.

    903.3.8.1 Number of sprinklers. Limited area sprinkler systems shall not exceed six sprinklers in any single fire area.

    903.3.8.2 Occupancy hazard classification. Only areas classified by NFPA 13 as Light Hazard or Ordinary Hazard Group 1 shall be permitted to be protected by limited area sprinkler systems.

    903.3.8.3 Piping arrangement. Where a limited area sprinkler system is installed in a building with an automatic wet standpipe system, sprinklers shall be supplied by the standpipe system. Where a limited area sprinkler system is installed in a building without an automatic wet standpipe system, water shall be permitted to be supplied by the plumbing system provided that the plumbing system is capable of simultaneously supplying domestic and sprinkler demands.

    903.3.8.4 Supervision. Control valves shall not be installed between the water supply and sprinklers unless the valves are of an approved indicating type that are supervised or secured in the open position.

    903.3.8.5 Calculations. Hydraulic calculations in accordance with NFPA 13 shall be provided to demonstrate that the available water flow and pressure are adequate to supply all sprinklers installed in any single fire area with discharge densities corresponding to the hazard classification.

    903.3.9 High-rise building floor control valves. Approved supervised indicating control valves shall be provided at the point of connection to the riser on each floor in high-rise buildings and Group I-2 occupancies having occupied floors located more than 75 feet above the lowest level of fire department vehicle access.

    903.3.10 Floor control valves. Floor control valves and waterflow detection assemblies shall be installed at each floor where any of the following occur: 1. Buildings where the floor level of the highest story is located more than 30 feet above the lowest level of fire department vehicle access.

    2. Buildings that are four or more stories in height. 3. Buildings that are two or more stories below the highest level of fire department vehicle access.

  • CPC § 603.3 High relevance — show source text

    Testing or maintenance shall be performed by a certified backflow assembly tester or repairer certified in accordance with ASSE/IAPMO/ANSI Series 5000 or any other additional certification approved by the Authority Having Jurisdiction.

    603.3 Backflow Prevention Devices, Assemblies, and Methods. Backflow prevention devices, assemblies, and methods shall comply with Section 603.3.1 through Section 603.3.12.

    603.3.1 Air Gap. The minimum air gap to afford backflow protection shall be in accordance with Table 603.3.1. 603.3.2 Atmospheric Vacuum Breaker (AVB). An atmospheric vacuum breaker consists of a body, a checking member, and an atmospheric port.

    603.3.3 Hose Connection Backflow Preventer. A hose connection backflow preventer consists of two independent check valves with an independent atmospheric vent between and a means of field testing and draining.

    603.3.4 Double Check Valve Backflow Prevention Assembly (DC). A double check valve backflow prevention assembly consists of two independently acting internally loaded check valves, four properly located test cocks, and two isolation valves.

    603.3.5 Pressure Vacuum Breaker Backflow Pre- vention Assembly (PVB). A pressure vacuum breaker backflow prevention assembly consists of a loaded air inlet valve, an internally loaded check valve, two properly located test cocks, and two isolation valves. This device shall be permitted to be installed indoors where provisions for spillage are provided. 603.3.6 Spill-Resistant Pressure Vacuum Breaker (SVB). A pressure-type vacuum breaker backflow prevention assembly consists of one check valve force loaded closed and an air inlet vent valve force loaded open to atmosphere, positioned downstream of the check valve and located between and including two tightly closing shutoff valves and test cocks. 603.3.7 Reduced-Pressure Principle Backflow Prevention Assembly (RP). A reduced-pressure principle backflow prevention assembly consists of two independently acting internally loaded check valves, a differential pressure relief valve, four properly located test cocks, and two isolation valves.

    603.3.8 Double Check Detector Fire Protection Backflow Prevention Assembly. A double check valve backflow prevention assembly with a parallel

    detector assembly consisting of a water meter and a double check valve backflow prevention assembly (DC).

    603.3.9 Reduced Pressure Detector Fire Protec- tion Backflow Prevention Assembly. A reducedpressure principle backflow prevention assembly with a parallel detector assembly consisting of a water meter and a reduced-pressure principle backflow prevention assembly (RP).

    603.3.10 Dual Check Backflow Preventer. A dual check backflow preventer consists of two independently acting check valves, force loaded to a normally closed position.

    603.3.11 Laboratory Faucet Backflow Preven- ters. Laboratory faucet backflow preventers shall comply with ASSE 1035.

    603.3.12 Backflow Preventer with Intermediate Atmospheric Vent. A backflow preventer with intermediate atmospheric vent consists of two independently acting check valves, force loaded to a normally closed position, and an intermediate chamber with a means for automatically venting to atmosphere, force loaded to a normally open position. 603.4 General Requirements. Assemblies shall comply with listed standards and be acceptable to the Authority Having Jurisdiction, with jurisdiction over the selection and installation of backflow prevention assemblies.

    **603.4.1 Backflow Prevention Valve.

  • CPC § 912.4.3 High relevance — show source text

    [F] 912.4.3 Physical protection. Where fire department connections are subject to impact by a motor vehicle, vehicle impact protection shall be provided in accordance with Section 312 of the California Fire Code .

    [F] 912.5 Signs. A metal sign with raised letters not less than 1 inch (25 mm) in size shall be mounted on all fire department connections serving automatic sprinklers, standpipes or fire pump connections. Such signs shall read: “AUTOMATIC SPRINKLERS,” “STANDPIPES,” “TEST CONNECTION,” “STANDPIPE AND AUTOSPKR” or “AUTOSPKR AND STANDPIPE,” or a combination thereof as applicable.

    [F] 912.5.1 Lettering. Each fire department connection (FDC) shall be designated by a sign with raised letters not less than 1 inch (25.4 mm) in height. For manual standpipe systems, the sign shall also indicate that the system is manual and that it is either wet or dry.

    [F] 912.5.2 Serving multiple buildings. Where a fire department connection (FDC) services multiple buildings, structures or locations, a sign shall be provided indicating the building, structures or locations served. Where the FDC does not serve the entire building, a sign shall be provided indicating the portions of the building served.

    [F] 912.5.3 Multiple or combined systems. Where combination or multiple system types are supplied by the fire department connection, the sign or combination of signs shall indicate both designated services.

    [F] 912.5.4 Indication of pressure. The sign also shall indicate the pressure required at the outlets to deliver the standpipe system demand.

    Exception: Where the pressure required is 150 pounds per square inch (1034 kPa) or less.

    [P] 912.6 Backflow protection. The potable water supply to automatic sprinkler and standpipe systems shall be protected against backflow as required by the Health and Safety Code Section 13114.7.

    SECTION 913—FIRE PUMPS

    [F] 913.1 General. Where provided, fire pumps for fire protection systems shall be installed in accordance with this section and NFPA 20.

    Exception: Pumps for automatic sprinkler systems installed in accordance with Section 903.3.1.3, or Section R313 of the Califor- nia Residential Code .

    [F] 913.2 Protection against interruption of service. The fire pump, driver and controller shall be protected in accordance with NFPA 20 against possible interruption of service through damage caused by explosion, fire, flood, earthquake, rodents, insects, windstorm, freezing, vandalism and other adverse conditions.

    913.2.1 Protection of fire pump rooms. Fire pumps shall be located in rooms that are separated from all other areas of the building by 2-hour fire barriers constructed in accordance with Section 707 or 2-hour horizontal assemblies constructed in accordance with Section 711, or both.

    Exceptions:

    1. In other than high-rise buildings, separation by 1-hour fire barriers constructed in accordance with Section 707 or 1hour horizontal assemblies constructed in accordance with Section 711, or both, shall be permitted in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2.
    2. Separation is not required for fire pumps physically separated in accordance with NFPA 20.
  • CPC § 9-69 High relevance — show source text

    2025 CALIFORNIA FIRE CODE 9-69

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

    FIRE PROTECTION AND LIFE SAFETY SYSTEMS

    912.5 Signs. A metal sign with raised letters not less than 1 inch (25 mm) in size shall be mounted on all fire department connections serving automatic sprinklers, standpipes or fire pump connections. Such signs shall read: “AUTOMATIC SPRINKLERS,” “STANDPIPES,” “TEST CONNECTION,” “STANDPIPE AND AUTOSPKR” or “AUTOSPKR AND STANDPIPE,” or a combination thereof as applicable.

    912.5.1 Lettering. Each fire department connection (FDC) shall be designated by a sign with letters not less than 1 inch (25.4 mm) in height. For manual standpipe systems, the sign shall also indicate that the system is manual and that it is either wet or dry.

    912.5.2 Serving multiple buildings. Where a fire department connection (FDC) services multiple buildings, structures or locations, a sign shall be provided indicating the building, structures or locations served. Where the FDC does not serve the entire building, a sign shall be provided indicating the portions of the building served.

    912.5.3 Multiple or combined systems. Where combination or multiple system types are supplied by the fire department connection, the sign or combination of signs shall indicate both designated services.

    912.5.4 Indication of pressure. The sign also shall indicate the pressure required at the outlets to deliver the standpipe system demand.

    Exception: Where the pressure required is 150 pounds per square inch (1034 kPa) or less.

    912.6 Backflow protection. The potable water supply to automatic sprinkler and standpipe systems shall be protected against backflow as required by the Health and Safety Code Section 13114.7.

    912.7 Inspection, testing and maintenance. Fire department connections shall be periodically inspected, tested and maintained in accordance with California Code of Regulations, Title 19, Division 1, Chapter 5 . Records of inspection, testing and maintenance shall be maintained.

    SECTION 913—FIRE PUMPS

    913.1 General. Where provided, fire pumps for fire protection systems shall be installed in accordance with this section and NFPA 20.

    Exception: Pumps for automatic sprinkler systems installed in accordance with Section 903.3.1.3, or Section P2904 of the Califor- nia Residential Code .

    913.2 Protection against interruption of service. The fire pump, driver and controller shall be protected in accordance with NFPA 20 against possible interruption of service through damage caused by explosion, fire, flood, earthquake, rodents, insects, windstorm, freezing, vandalism and other adverse conditions.

    913.2.1 Protection of fire pump rooms. Rooms where fire pumps are located shall be separated from all other areas of the building in accordance with Section 913.2.1 of the California Building Code .

  • CPC § 420.1 High relevance — show source text

    420.1| |CSA B45.8-2018/IAPMO
    Z403-2018|Terrazzo, Concrete, Composite Stone, and Natural Stone
    Plumbing Fixtures|Fixtures|407.1, 420.1| |ASME A112.3.4-2018/CSA
    B45.9-2018|Macerating Toilet Systems and Waste-Pumping Systems for
    Plumbing Fixtures|Fixtures|710.13| |ASME A112.19.7-
    2020/CSA B45.10-2020|Hydromassage Bathtub Systems|Fixtures|409.1, 409.6.1|

    2025 CALIFORNIA PLUMBING CODE 345

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

    REFERENCED STANDARDS

    TABLE 1701.1 (continued) REFERENCED STANDARDS

    STANDARD NUMBER STANDARD TITLE APPLICATION REFERENCED
    SECTION
    CSA B45.11-2017/IAPMO
    Z401-2017 (R2021)    		 Glass Plumbing Fixtures Fixtures 407.1
    CSA B45.12-2013/IAPMO
    Z402-2013 (R2018)    		 Aluminum and Copper Plumbing Fixtures Fixtures 407.1, 408.1, 409.1,
    420.1
    ASME A112.19.5-
    2017/CSA B45.15-2017    		 Flush Valves and Spuds for Water Closets, Urinals, and Tanks Fixtures 413.3
    ASME A112.4.2-2021/CSA
    B45.16-2021    		 Personal Hygiene Devices for Water Closets Fixtures 411.4
    CSA B64.1.1-2021 Atmospheric Vacuum Breakers (AVB) Backflow Protection Table 603.2
    CSA B64.1.2-2021 Pressure Vacuum Breakers (PVB) Backflow Protection Table 603.2
    CSA B64.2.1.1-2021 Hose Connection Dual Check Vacuum Breakers (HCDVB) Backflow Protection Table 603.2
    CSA B64.4-2021 Reduced Pressure Principle (RP) Backflow Preventers Backflow Protection Table 603.2
    CSA B64.4.1-2021 Reduced Pressure Principle Backflow Preventers for Fire Pro-
    tection Systems (RPF)    		 Backflow Protection Table 603.2
    CSA B64.5-2021 Double Check Valve (DCVA) Backflow Preventers Backflow Protection Table 603.2
    CSA B64.5.1-2021 Double Check Valve Backflow Preventers for Fire Protection
    Systems (DCVAF)    		 Backflow Protection Table 603.2
    CSA B79-2008 (R2018) Commercial and Residential Drains and Cleanouts Fixtures 418.1, Table 707.2
    ASME A112.18.1-
    2018/CSA B125.1-2018    		 Plumbing Supply Fittings Fittings 408.4, 417.1, 417.2,
    417.3, 417.4, 417.6,
    603.5.20
    ASME A112.18.
  • CPC § 16-2021 High relevance — show source text

    16-2021|Personal Hygiene Devices for Water Closets|Fixtures|411.4| |CSA B64.1.1-2021|Atmospheric Vacuum Breakers (AVB)|Backflow Protection|Table 603.2| |CSA B64.1.2-2021|Pressure Vacuum Breakers (PVB)|Backflow Protection|Table 603.2| |CSA B64.2.1.1-2021|Hose Connection Dual Check Vacuum Breakers (HCDVB)|Backflow Protection|Table 603.2| |CSA B64.4-2021|Reduced Pressure Principle (RP) Backflow Preventers|Backflow Protection|Table 603.2| |CSA B64.4.1-2021|Reduced Pressure Principle Backflow Preventers for Fire Pro-
    tection Systems (RPF)|Backflow Protection|Table 603.2| |CSA B64.5-2021|Double Check Valve (DCVA) Backflow Preventers|Backflow Protection|Table 603.2| |CSA B64.5.1-2021|Double Check Valve Backflow Preventers for Fire Protection
    Systems (DCVAF)|Backflow Protection|Table 603.2| |CSA B79-2008 (R2018)|Commercial and Residential Drains and Cleanouts|Fixtures|418.1, Table 707.2| |ASME A112.18.1-
    2018/CSA B125.1-2018|Plumbing Supply Fittings|Fittings|408.4, 417.1, 417.2,
    417.3, 417.4, 417.6,
    603.5.20| |ASME A112.18.2-
    2020/CSA B125.2-2020|Plumbing Waste Fittings|Fittings|404.1, 408.5| |CSA B125.3-2018|Plumbing Fittings|Fittings|409.4(1), 410.3(1)| |CSA B125.5-2011/IAPMO
    Z600-2011 (R2016)|Flexible Water Connectors with Excess Flow Shut-off Device|Miscellaneous|604.5| |ASME A112.18.6-
    2017/CSA B125.6-2017
    (R2021)|Flexible Water Connectors|Piping|604.5, 604.13| |ASSE 1002-2020/ASME
    A112.1002-2020/CSA
    B125.12-2020|Anti-Siphon Fill Valves for Water Closet Tanks|Backflow Protection|413.3, Table 603.2| |ASME A112.4.14-
    2017/CSA B125.14-2017|Manually Operated Valves for Use in Plumbing Systems|Valves|606.1| |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 1037-2020/ASME
    A112.1037-2020/CSA
    B125.37-2020|Pressurized Flushing Devices for Plumbing Fixtures|Backflow Protection|413.2| |ASSE 1070-2020/ASME
    A112.

Frequently asked questions

Do all fire department connections automatically require a backflow preventer?

Not automatically — the CPC requires a reduced-pressure style device only if the FDC is located less than 1700 ft from a nonpotable source usable by fire crews (§ 603.5.14.1) or if chemicals/antifreeze are present in the system (§ 603.5.14.2). Otherwise, other rules or NFPA standards may apply and local adoption/enforcement should be confirmed.

Can I use a double-check assembly for a sprinkler system?

Not when the conditions in § 603.5.14.1 or § 603.5.14.2 are met. The CPC specifically requires a reduced-pressure style assembly (or reduced-pressure detector type) where a nonpotable source is nearby or chemicals are present.

Who verifies the hydraulic impact of adding a backflow device?

The designer/engineer responsible for the sprinkler hydraulics must account for the device pressure drop and verify satisfactory operation; retrofitted devices require re-checking of the hydraulics per § 603.5.14.3. The AHJ may require calculations or test evidence.

Where do I find the exact device pressure loss to use in calculations?

The CPC requires you to account for the pressure drop but does not provide device loss values; obtain published loss data or manufacturer test results for the chosen RP/RPD and use those values in your hydraulic calculations as required by § 603.5.14.3.

Does the CPC require annual testing of these assemblies?

The CPC requires backflow assemblies to be tested and maintained in accordance with Chapter 6 requirements and by qualified testers per the code (see Chapter 6 backflow tester qualifications), but the specific inspection/test frequency for fire protection assemblies may also be governed by the Fire Code and Title 19 requirements; confirm applicable testing schedules with the AHJ.

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