CPC · California Plumbing Code

Are there lead-content limits for water heater piping and outlets?

Q: What about solder used when installing a water heater?

Solder and flux used in potable piping are limited to 0.2% lead under § 604.2 ; ensure solders/fluxes used during installation meet that limit.

For homeowners: California requires water heaters and their connected potable plumbing to meet the statewide lead rules — the wetted surfaces of pipes, fittings and fixtures must average no more than 0.25% lead, and solder/flux must be ≤0.2% (see §504.7 and §604.2).

Ask a question free See coverage

Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

Water heaters installed in California must meet the statewide lead-content limits for plumbing materials: water heaters must comply with the lead-content rules of § 604.2, as required by § 504.7. § 604.2 limits the lead in pipes, fittings, plumbing fittings, and fixtures that convey or dispense water for human consumption to a weighted average of 0.25 percent on the wetted surfaces, and limits solder and flux used in potable systems to 0.2 percent.

For water heaters and their connected piping/outlets, the single controlling limit is that the wetted surfaces of all potable water components average no more than 0.25% lead (with solder/flux limited to 0.2%).

Requirements in detail

Scope and controlling sections

The water-heater specific clause is § 504.7, which ties water heaters to the material/lead rules in § 604.2.
The material rule that applies to the water heater and its piping/outlets is § 604.2 (lead content limits for pipes, pipe fittings, plumbing fittings, and fixtures).

What “weighted average” and “wetted surfaces” mean (practical effect)

The code requires the average lead content of all wetted surfaces of the pipes, fittings, fixtures, and plumbing fittings that contact potable water to be no more than 0.25% (weighted by the relative amount of wetted surface each part contributes). Solder and flux used in potable piping are limited separately to 0.2% lead.
This means you evaluate each component that contacts the water (pipe sections, fittings, valves, faucets, connectors) and compute a weighted average across their wetted surfaces to confirm compliance.

Quick decision table

Decision item	Limit / Value	Code Reference
Max lead content — weighted average of wetted surfaces (pipes/fittings/fixtures for potable water)	0.25%	§ 604.2
Max lead content — solder & flux used in potable systems	0.2%	§ 604.2
Exception — nonpotable services (manufacturing, irrigation, etc.)	Exempt from 0.25% potable limit	§ 604.2 Exceptions
Exception — certain large valves & devices (size threshold)	Devices 2 inches (50 mm) or larger (e.g., flush valves, main gate valves) are excepted	§ 604.2 Exceptions
Lead content allowed for non-drinking water supply pipes & fittings	8% maximum	§ 604.2.1

Materials and connected items to evaluate

Pipes, pipe fittings, plumbing fittings, and fixtures that will be wetted by potable water.
Solder and flux used in those potable piping systems (separate 0.2% limit).
Components intended only for nonpotable uses are excluded from the potable limits, but have their own allowable maximum (see § 604.2.1).

Exceptions & special cases

Nonpotable systems (manufacturing, irrigation, outdoor watering, etc.) are not required to meet the 0.25% potable-water weighted average limit; for those uses § 604.2.1 allows up to 8% lead for supply pipe and fittings.
The code explicitly excepts certain large devices — flush valves, fill valves, flushometer valves, tub fillers, shower valves, service saddles, or water distribution main gate valves that are 2 inches (50 mm) or larger — from the potable lead limit of § 604.2. Check whether the specific outlet at or downstream of a water heater falls into that list.
The water-heater section does not create a separate lead limit; it simply applies the general material/lead rules (so compliance requires looking at § 604.2 and related material sections). § 504.7 is the link.

Common mistakes

Assuming the water heater body or its factory fittings are automatically exempt. The code requires that the assembly connected to potable water meet § 604.2; do not assume the heater or its shipped connectors are compliant without verifying. § 504.7 → § 604.2.
Forgetting the solder/flux limit. Even if the pipes and fittings meet 0.25% weighted average, using solder/flux over 0.2% lead would violate § 604.2 for potable systems.
Treating the 0.25% as a per-piece limit instead of a weighted average across wetted surfaces. Some high-lead components can be acceptable only if their contribution is small enough relative to low-lead components to keep the weighted average ≤0.25%.
Overlooking exceptions: large valves (≥ 2 in. (50 mm)) and genuine nonpotable services may be carved out; don’t apply the potable limits blindly.

Worked example — applying the weighted-average rule

Scenario: A small water-heater run uses the following wetted components (simplified to surface-area proxies):

Copper pipe run (wetted area = 10 units) with lead content 0.05% (modern copper alloy).
Brass shutoff valve (wetted area = 1 unit) with lead content 1.5%.
Faucet/fixture at the outlet (wetted area = 1 unit) with lead content 0.8%.

Compute weighted average lead content:

Total wetted-area units = 10 + 1 + 1 = 12 units.
Sum of (lead% × area) = (0.05% × 10) + (1.5% × 1) + (0.8% × 1) = 0.5% + 1.5% + 0.8% = 2.8% (aggregate percent‑units).
Weighted average = 2.8% ÷ 12 = 0.233%.

Result: 0.233% ≤ 0.25%, so the assembly complies with the potable lead limit in § 604.2 (provided solder/flux used also meets the 0.2% limit). If the shutoff valve’s lead content or its wetted surface were larger, the average could exceed 0.25% and fail.

Notes on this example:

This arithmetic follows the code concept of a wetted-surface weighted average in § 604.2; the code does not prescribe a specific calculation format, so compute using relative wetted surface areas or volumes as appropriate to your design.

Related provisions

§ 504.7 — Water heaters shall comply with the lead content requirements of § 604.2.
§ 604.2 — Lead-content limits for pipes, fittings, plumbing fittings, fixtures; solder/flux limit.
§ 604.2.1 — Lead content of water supply pipe and fittings for non‑drinking water applications (max 8%).
Section listing for 604.0 (Materials for water supply and distribution) and related subsections including 604.5 (Flexible Connectors) and 604.11 (Solder) — see chapter headings and materials tables for product standards and marking requirements that interact with lead-content compliance.

Code references

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

CPC § 501.1 High relevance — show source text
Table 501.1(1) Water Heaters . . . . . . . . . . . . . . . .83

501.2 California Energy Code Water Heating System Requirements . . . . . . . . . . . . . . . . .83

502.0 Permits . . . . . . . . . . . . . . . . . . . . . .83

502.1 General . . . . . . . . . . . . . . . . . . . . . .83

503.0 Inspection . . . . . . . . . . . . . . . . . . . .83

503.1 Inspection of Chimneys or Vents . . .83

503.2 Final Water Heater Inspection . . . .83

504.0 Water Heater Requirements . . . . . .83

504.1 Location . . . . . . . . . . . . . . . . . . . . .83

Table 501.1(2) First Hour Rating . . . . . . . . . . . . . .83

504.2 Vent . . . . . . . . . . . . . . . . . . . . . . . .84

504.3 Clearance . . . . . . . . . . . . . . . . . . . .84

504.4 Pressure-Limiting Devices . . . . . . .84

504.5 Temperature-Limiting Devices . . . .84

504.6 Temperature, Pressure, and Vacuum Relief Devices . . . . . . . . .84

504.7 Lead Content . . . . . . . . . . . . . . . . .84

505.0 Oil-Burning and Other Water Heaters . . . . . . . . . . . . . . . . . . . . . .84

505.1 Water Heaters . . . . . . . . . . . . . . . .84

505.2 Safety Devices . . . . . . . . . . . . . . . .84

505.3 Oil-Fired Water Heaters . . . . . . . . .84

505.4 Indirect-Fired Water Heaters . . . . .84

506.0 Air for Combustion and

Ventilation . . . . . . . . . . . . . . . . . . . .84

506.1 General . . . . . . . . . . . . . . . . . . . . . .84

506.2 Indoor Combustion Air . . . . . . . . . .85

506.3 Indoor Opening Size and Location . . . . . . . . . . . . . . . . . . . . .85

506.4 Outdoor Combustion Air . . . . . . . . .85

506.5 Combination Indoor and

Outdoor Combustion Air . . . . . . . . .87

506.6 Engineered Installations . . . . . . . . .87

506.7 Mechanical Combustion Air Supply . . . . . . . . . . . . . . . . . . . . . . .87

506.8 Louvers, Grilles, and Screens . . . .87

506.9 Combustion Air Ducts . . . . . . . . . . .87

507.0 Appliance and Equipment Installation Requirements . . . . . . . .88

507.1 Dielectric Insulator . . . . . . . . . . . . .88
CPC § 3.785 High relevance — show source text
For SI units: 1 gallon = 3.785 L

Notes: 1 The first-hour rating is found on the “Energy Guide” label. 2 Solar water heaters shall be sized to meet the appropriate first-hour rating as shown in the table.

2025 CALIFORNIA PLUMBING CODE 83

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

WATER HEATERS

Exception: Where acceptable to the Authority Having Jurisdiction, gasketing of non-combustible or limitedcombustible material shall be permitted to be applied to the frame, provided closing and latching of the door are not inhibited.

504.2 Vent. Water heaters of other than the direct-vent type shall be located as close as practical to the chimney or gas vent. 504.3 Clearance. The clearance requirements for water heaters shall comply with Section 504.3.1 or Section 504.3.2.

504.3.1 Listed Water Heaters. The clearances shall not be such as to interfere with combustion air, draft hood clearance and relief, and accessibility for servicing. Listed water heaters shall be installed in accordance with their listings and the manufacturer’s installation instructions. 504.3.2 Unlisted Water Heaters. Except as otherwise permitted in this code, unlisted water heaters shall be approved by the Authority Having Jurisdiction prior to being installed. Clearance for unlisted water heaters shall be not less than 12 inches (305 mm) on all sides. Combustible floors under unlisted water heaters shall be protected in an approved manner. {NFPA 54-2018:10.27.2.2} 504.4 Pressure-Limiting Devices. A water heater installation shall be provided with overpressure protection using an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. Pressure relief devices shall have a pressure setting greater than the water service pressure and not exceed 150 psi (1034 kPa) as required in Section 608.4. 504.5 Temperature Limiting Devices. A water heater installation or a hot water storage vessel installation shall be provided with overtemperature protection by means of an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. {NFPA 54:10.26.5} 504.6 Temperature, Pressure, and Vacuum Relief Devices. Temperature, pressure, and vacuum relief devices or combinations thereof, and automatic gas shutoff devices shall be installed in accordance with the terms of their listings and the manufacturer’s installation instructions. A shutoff valve shall not be placed between the relief valve and the water heater or on discharge pipes between such valves and the atmosphere. The hourly British thermal units (Btu) (kW•h) discharge capacity or the rated steam relief capacity of the device shall be not less than the input rating of the water heater. {NFPA 54:10.26.6} Discharge piping shall be installed in accordance with Section 608.5.

504.7 Lead Content. Water heaters shall comply with the lead content requirements of Section 604.2.
CPC § 1.5 High relevance — show source text
(3) The building official shall not give final permit approval of any PEX plumbing installation unless he or she finds that the material has been installed in compliance with the requirements of the code, includ- ing the requirements to flush and tag the systems.

(4) Any contractor or subcontractor found to have failed to comply with the PEX flushing requirements shall be subject to the penalties in Health and Safety Code, Division 13, Part 1.5, Chapter 6 (Section 17995, et seq.).

604.2 Lead Content. The maximum allowable lead content in pipes, pipe fittings, plumbing fittings, and fixtures intended to convey or dispense water for human consumption shall be not more than a weighted average of 0.25 percent with respect to the wetted surfaces of pipes, pipe fittings, plumbing fittings,

and fixtures. For solder and flux, the lead content shall be not more than 0.2 percent where used in piping systems that convey or dispense water for human consumption.

Note: See Sections 116875 and 116876 of the Health and Safety Code for the maximum lead content of pipes, pipe or plumbing fittings, or fixtures intended to convey or dispense water for human consumption.

Exceptions:

(1) Pipes, pipe fittings, plumbing fittings, fixtures, or backflow preventers used for nonpotable services such as manufacturing, industrial processing, irrigation, outdoor watering, or any other uses where the water is not used for human consumption.

(2) Flush valves, fill valves, flushometer valves, tub fillers, shower valves, service saddles, or water distribution main gate valves that are 2 inches (50 mm) in diameter or larger.

604.2.1 Lead Content of Water Supply Pipe and Fittings. Pipes, pipe fittings, valves, and faucets utilized in the water supply system for non-drinking water applications shall have a maximum of 8 percent lead content.

604.3 Copper or Copper Alloy Tube. Copper or copper alloy tube for water piping shall have a weight of not less than Type L.

Exception: Type M copper or copper alloy tubing shall be permitted to be used for water piping where piping is aboveground in, or on, a building or underground outside of struc tures.

604.4 Hard-Drawn Copper or Copper Alloy Tubing. Hard-drawn copper or copper alloy tubing for water supply and distribution in addition to the required incised marking shall be marked in accordance with ASTM B88. The colors shall be: Type K, green; Type L, blue; and Type M, red.

604.5 Flexible Connectors. Flexible water connectors

shall be installed in accessible locations, and where under continuous pressure shall comply with ASME A112.18.6/CSA B125.6. Flexible water connectors with an excess flow shut off device shall comply with CSA B125.5/IAPMO Z600.

604.6 Cast-Iron Fittings. Cast-iron fittings up to and including 2 inches (50 mm) in size, where used in connection with potable water piping, shall be galvanized.

604.7 Malleable Iron Fittings. Malleable iron water fittings shall be galvanized.

604.8 Previously Used Piping and Tubing. Piping and tubing that has previously been used for a purpose other than for potable water systems shall not be used.
CPC § 603.3 High relevance — show source text
603.3 Backflow Prevention Devices, Assemblies, and Methods . . . . . .140

603.4 General Requirements . . . . . . . . .140

603.5 Specific Requirements . . . . . . . . .141

Table 603.2 Backflow Prevention Devices, Assemblies, and Methods . . . . . .142

Table 603.3.1 Minimum Air Gaps for Water Distribution . . . . . . . . . . . . . . . . . .144

604.0 Materials . . . . . . . . . . . . . . . . . . . .146

604.1 Pipe, Tube, and Fittings . . . . . . . .146

604.2 Lead Content . . . . . . . . . . . . . . . .147

604.3 Copper or Copper Alloy Tube . . .147

604.4 Hard-Drawn Copper or Copper Alloy Tubing . . . . . . . . . . . . . . . . .147

604.5 Flexible Connectors . . . . . . . . . . .147

604.6 Cast-Iron Fittings . . . . . . . . . . . . .147

604.7 Malleable Iron Fittings . . . . . . . . .147

604.8 Previously Used Piping and Tubing . . . . . . . . . . . . . . . . . . . . . .147

604.9 Epoxy Coating . . . . . . . . . . . . . . .147

604.10 Plastic Materials . . . . . . . . . . . . . .147

Table 604.1 Materials for Building Supply and Water Distribution Piping and Fittings . . . . . . . . . . . . . . . . . .148

604.11 Solder . . . . . . . . . . . . . . . . . . . . . .149

604.12 Flexible Corrugated Connectors . .149

604.13 Water Heater Connectors . . . . . . .149

605.0 Joints and Connections . . . . . . . .149

605.1 Copper or Copper Alloy Pipe, Tubing, and Joints . . . . . . . . . . . .149

605.2 CPVC Plastic Pipe and Joints . . .150

605.3 CPVC/AL/CPVC Plastic Pipe and Joints . . . . . . . . . . . . . . . . . . .150

605.4 Ductile Iron Pipe and Joints . . . . .150

605.5 Galvanized Steel Pipe and Joints . . . . . . . . . . . . . . . . . . . . . .151

605.6 PE Plastic Pipe/Tubing and Joints . . . . . . . . . . . . . . . . . . . . . .151

605.7 PE-AL-PE Plastic Pipe/Tubing and Joints . . . . . . . . . . . . . . . . . . .151

605.8 PE-RT . . . . . . . . . . . . . . . . . . . . . .151

605.9 PEX Plastic Tubing and Joints . . .151

605.10 PEX-AL-PEX Plastic Tubing and Joints . . . . . . . . . . . . . . . . . . .152

CPC § 604.2.1 High relevance — show source text

604.2.1 Lead Content of Water Supply Pipe and Fittings. Pipes, pipe fittings, valves, and faucets utilized in the water supply system for non-drinking water applications shall have a maximum of 8 percent lead content.

604.3 Copper or Copper Alloy Tube. Copper or copper alloy tube for water piping shall have a weight of not less than Type L.

Exception: Type M copper or copper alloy tubing shall be permitted to be used for water piping where piping is aboveground in, or on, a building or underground outside of struc tures.

604.4 Hard-Drawn Copper or Copper Alloy Tubing. Hard-drawn copper or copper alloy tubing for water supply and distribution in addition to the required incised marking shall be marked in accordance with ASTM B88. The colors shall be: Type K, green; Type L, blue; and Type M, red.

604.5 Flexible Connectors. Flexible water connectors

shall be installed in accessible locations, and where under continuous pressure shall comply with ASME A112.18.6/CSA B125.6. Flexible water connectors with an excess flow shut off device shall comply with CSA B125.5/IAPMO Z600.

604.6 Cast-Iron Fittings. Cast-iron fittings up to and including 2 inches (50 mm) in size, where used in connection with potable water piping, shall be galvanized.

604.7 Malleable Iron Fittings. Malleable iron water fittings shall be galvanized.

604.8 Previously Used Piping and Tubing. Piping and tubing that has previously been used for a purpose other than for potable water systems shall not be used.

604.9 Epoxy Coating. The epoxy coating used on existing, underground steel building supply piping shall comply with NSF/ANSI/CAN 61 and AWWA C210.

604.10 Plastic Materials. Approved plastic materials shall be permitted to be used in building supply piping, provided that where metal building supply piping is used for electrical grounding purposes, replacement piping, therefore, shall be of like materials.

2025 CALIFORNIA PLUMBING CODE 147

WATER SUPPLY AND DISTRIBUTION

TABLE 604.1

MATERIALS FOR BUILDING SUPPLY AND WATER DISTRIBUTION PIPING AND FITTINGS

MATERIAL	BUILDING SUPPLY PIPE AND FITTINGS	WATER DISTRIBUTION PIPE AND FITTINGS	REFERENCED STANDARD(S) PIPE	REFERENCED STANDARD(S) FITTINGS
Copper and Copper Alloys	X	X	ASTM B42, ASTM B43, ASTM B75, ASTM B88, ASTM B135, ASTM B251, ASTM B302, ASTM B447	ASME B16.15, ASME B16.18, ASME B16.22, ASME B16.26, ASME B16.502, ASME B16.51, ASSE 1061, ASTM F3226, AWWA C606, CSA B242, IAPMO PS 53, IAPMO PS 117
CPVC	X	X	ASTM D2846, ASTM F441, ASTM F442, CSA B137.

CPC § 422.1 High relevance — show source text
422.1 Fixture Count . . . . . . . . . . . . . . . . .67

422.2 Separate Facilities . . . . . . . . . . . . .68

422.3 Fixture Requirements for Special Occupancies . . . . . . . . . . .68

422.4 Toilet Facilities Serving Employees and Customers . . . . . .68

422.5 Toilet Facilities for Workers . . . . . .69

422.6 Water Closet Compartment . . . . . .69

422.7 Urinal Partitions . . . . . . . . . . . . . . .69

422.8 Cosmetology . . . . . . . . . . . . . . . . .69

422.9 Cosmetology Establishments . . . . .69

422.10 Commissaries Serving Mobile Food Preparation Units . . . . . . . . .69

422.11 Employee Lavatories in Food Establishments . . . . . . . . . . .69

Table 422.1 Minimum Plumbing Facilities . . . . .70

Table 4-1 Occupant Load Factor

[BSC and DSA-SS] . . . . . . . . . . . .75

Table 4-2 Minimum Plumbing Facilities

[OSHPD 1, 2, 3, 4 & 5] . . . . . . . . .76

CHAPTER 5 WATER HEATERS . . . . . . . . . . . .81

501.0 General . . . . . . . . . . . . . . . . . . . . . .83

501.1 Applicability . . . . . . . . . . . . . . . . . . .83

Table 501.1(1) Water Heaters . . . . . . . . . . . . . . . .83

501.2 California Energy Code Water Heating System Requirements . . . . . . . . . . . . . . . . .83

502.0 Permits . . . . . . . . . . . . . . . . . . . . . .83

502.1 General . . . . . . . . . . . . . . . . . . . . . .83

503.0 Inspection . . . . . . . . . . . . . . . . . . . .83

503.1 Inspection of Chimneys or Vents . . .83

503.2 Final Water Heater Inspection . . . .83

504.0 Water Heater Requirements . . . . . .83

504.1 Location . . . . . . . . . . . . . . . . . . . . .83

Table 501.1(2) First Hour Rating . . . . . . . . . . . . . .83

504.2 Vent . . . . . . . . . . . . . . . . . . . . . . . .84

504.3 Clearance . . . . . . . . . . . . . . . . . . . .84

504.4 Pressure-Limiting Devices . . . . . . .84

504.5 Temperature-Limiting Devices . . . .84

504.6 Temperature, Pressure, and Vacuum Relief Devices . . . . . . . . .84

504.7 Lead Content . . . . . . . . . . . . . . . . .84
CPC § 54-2018 High relevance — show source text
Clearance for unlisted water heaters shall be not less than 12 inches (305 mm) on all sides. Combustible floors under unlisted water heaters shall be protected in an approved manner. {NFPA 54-2018:10.27.2.2} 504.4 Pressure-Limiting Devices. A water heater installation shall be provided with overpressure protection using an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. Pressure relief devices shall have a pressure setting greater than the water service pressure and not exceed 150 psi (1034 kPa) as required in Section 608.4. 504.5 Temperature Limiting Devices. A water heater installation or a hot water storage vessel installation shall be provided with overtemperature protection by means of an approved, listed device installed in accordance with the terms of its listing and the manufacturer’s installation instructions. {NFPA 54:10.26.5} 504.6 Temperature, Pressure, and Vacuum Relief Devices. Temperature, pressure, and vacuum relief devices or combinations thereof, and automatic gas shutoff devices shall be installed in accordance with the terms of their listings and the manufacturer’s installation instructions. A shutoff valve shall not be placed between the relief valve and the water heater or on discharge pipes between such valves and the atmosphere. The hourly British thermal units (Btu) (kW•h) discharge capacity or the rated steam relief capacity of the device shall be not less than the input rating of the water heater. {NFPA 54:10.26.6} Discharge piping shall be installed in accordance with Section 608.5.

504.7 Lead Content. Water heaters shall comply with the lead content requirements of Section 604.2.

505.0 Oil-Burning and Other Water Heaters. 505.1 Water Heaters. Water heaters deriving heat from fuels or types of energy other than gas shall comply with the standards referenced in Table 501.1(1), Section 505.3, or Section 505.4. Vents or chimneys for such appliances shall be of approved types. An adequate supply of air for combustion and for adequate ventilation of heater rooms or compartments shall be provided. Each such appliance shall be installed in a

location approved by the Authority Having Jurisdiction and local and state fire-prevention agencies. 505.2 Safety Devices. Storage-type water heaters and hot water boilers deriving heat from fuels or types of energy other than gas, shall be provided with, in addition to the primary temperature controls, an over-temperature safety protection device that complies with and is installed in accordance with nationally recognized applicable standards for such devices and a combination temperature and pressure-relief valve.

505.3 Oil-Fired Water Heaters. Oil-fired water heaters

shall be installed in accordance with NFPA 31.

505.4 Indirect-Fired Water Heaters. Indirect-fired water heaters shall be in accordance with the applicable sections of the ASME Boiler and Pressure Vessel Code or shall comply with one of the other applicable standards shown in Table 501.1(1). Each water heater shall bear a label in accordance with ASME requirements, or an approved testing agency, certifying and attesting that such an appliance has been tested, inspected and meets the requirements of the applicable standards or code. 505.4.1 Single-Wall Heat Exchanger. An indirectfired water heater that incorporates a single-wall heat exchanger shall be in accordance with the following requirements:

CPC § 1323.1.5 High relevance — show source text

(6) Add the pressure loss for each section of piping, from the source equipment location to the outlet or

inlet, to determine the total system pressure loss to each outlet or inlet. The total system pressure loss in the piping to each outlet or inlet shall not exceed the values specified in Table 1323.1.5(2).

TABLE 1323.1.5(1) SYSTEM SIZING – FLOW REQUIREMENTS FOR STATION OUTLETS AND INLETS [1]

NUMBER OF OUTLETS AND INLETS TERMINAL UNITS PER FACILITY	DIVERSITY PERCENTAGE OF AVERAGE FLOW PER OUTLETS AND INLETS TERMINAL UNITS	MINIMUM PERMISSIBLE SYSTEM FLOW OF ALL PRESSURIZED MEDICAL GAS SYSTEMS2 (standard cubic feet per minute)
1–10	100%	Actual Demand
11–25	75%	7.0
26–50	50%	13.1
51–100	50%	17.5

Notes: 1 Flow rates of station outlets and inlets in accordance with Table 1305.2. 2 The minimum system flow is the average outlets and inlets flow times the number of station outlets and inlets times the diversity percentage.

TABLE 1323.1.5(2) MAXIMUM PERMITTED PRESSURE LOSS IN

MEDICAL GAS AND MEDICAL VACUUM SYSTEMS

TYPE OF SYSTEM	MAXIMUM ALLOWABLE SYSTEM PRESSURE LOSS (psi)
Medical Air	5
Nitrogen	15
Nitrous Oxide	5
Carbon Dioxide	5
Oxygen	5
Medical Vacuum	4 inches of mercury

For SI units: 1 pound-force per square inch = 6.8947 kPa, 1 inch of mercury = 3.386 kPa

1323.1.6 Engineering Methods. For conditions other than those covered by Section 1323.1.4, such as longer runs of greater gas or vacuum demands, the size of each medical gas or vacuum piping system shall be determined by standard engineering methods acceptable to the Authority Having Jurisdiction, and each system shall be so designed that the total pressure drop or gain between the source equipment and an outlet or inlet shall not exceed the allowable pressures shown in Table 1305.1. 1323.2 Pipe Protection. Piping shall be protected against freezing, corrosion, and physical damage. [NFPA 99:5.1.10.11.2] 1323.2.1 Exposed Piping. Piping exposed in corridors and other areas where subject to physical damage from the movement of carts, stretchers, portable equipment, or vehicles shall be protected. [NFPA 99:5.1.10.11.2.1] 1323.2.2 Underground Piping. Piping underground within buildings or embedded in concrete floors or walls shall be installed in a continuous conduit. [NFPA 99:5.1.10.11.2.2]

TABLE 1323.1.5(1) SYSTEM SIZING – FLOW REQUIREMENTS FOR STATION OUTLETS AND INLETS [1]

CPC § 110.3 High relevance — show source text
1. Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature. Exception to Section 110.3(c)1: Systems covered by California Plumbing Code Section 613.0 shall instead follow the requirements of that section.
2. Controls for hot water distribution systems. Service hot water systems with circulating pumps or with electrical heat trace systems shall be capable of automatically turning off the system. Exception to Section 110.3(c)2: Systems serving healthcare facilities.
3. Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have: A. External insulation with an installed R -value of at least R-3.5; or
B. Internal and external insulation with a combined R -value of at least R-16; or

C. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot. 4. Water heating recirculation loops serving multiple dwelling units, high-rise residential, hotel/motel, and nonresiden- tial occupancies. A water heating recirculation loop is a type of hot water distribution system that reduces the time needed to deliver hot water to fixtures that are distant from the water heater, boiler or other water heating equipment. The recirculation loop is comprised of a supply portion, connected to branches that serve multiple dwelling units, guest rooms, or fixtures and a return portion that completes the loop back to the water heating equipment. A water heating recirculation loop shall meet the following requirements: A. Air release valve or vertical pump installation. An automatic air release valve shall be installed on the recirculation loop piping on the inlet side of the recirculation pump and no more than 4 feet from the pump. This valve shall be mounted on top of a vertical riser at least 12 inches in length and shall be accessible for replacement and repair. Alternatively, the pump shall be installed on a vertical section of the return line. B. Recirculation loop backflow prevention. A check valve or similar device shall be located between the recirculation pump and the water heating equipment to prevent water from flowing backwards though the recirculation loop. C. Equipment for pump priming. A hose bibb shall be installed between the pump and the water heating equipment. An isolation valve shall be installed between the hose bibb and the water heating equipment. This hose bibb is used for bleeding air out of the pump after pump replacement. D. Pump isolation valves. Isolation valves shall be installed on both sides of the pump. These valves may be part of the flange that attaches the pump to the pipe. One of the isolation valves may be the same isolation valve as in Item C. E. Cold water supply and recirculation loop connection to hot water storage tank. Storage water heaters and boilers shall be plumbed in accordance with the manufacturer’s specifications The cold water piping and the recirculation loop piping shall not be connected to the hot water storage tank drain port. F. Cold water supply backflow prevention. A check valve shall be installed on the cold water supply line between the hot water system and the next closest tee on the cold water supply line.
CPC § 0.293 High relevance — show source text
automatic storage
30 to 40 gallon tank
Water heater, automatic storage
50 gallon tank
Water heater, automatic instantaneous
Capacity at 2 gallons per minute
Capacity at 4 gallons per minute
Capacity at 6 gallons per minute
Water heater, domestic, circulating or
side-arm|

35 000

50 000

142 800
285 000
428 400

35 000| |

Cooking Appliances
Range, freestanding, domestic
Built-in oven or broiler unit, domestic
Built-in top unit, domestic|
65 000
25 000
40 000| |

Other Appliances
Refrigerator
Clothes dryer, Type 1 (domestic)
Gas fireplace direct-vent
Gas log
Barbecue
Gaslight|
3000
35 000
40 000
80 000
40 000
2500|

For SI units: 1000 British thermal units per hour = 0.293 kW

1208.3.2 Sizing Methods. Gas piping shall be sized in accordance with one of the following:

(1) Pipe sizing tables or sizing equations in this chap ter.

(2) Sizing tables included in a listed piping system manufacturer’s installation instructions.

(3) Engineering methods. [NFPA 54:5.3.3]

1208.3.3 Allowable Pressure Drop. The design pressure loss in a piping system from the point of delivery to

TABLE 1208.3.1

APPROXIMATE GAS INPUT FOR

TYPICAL APPLIANCES

[NFPA 54: TABLE A.5.3.2.1]

«

«

«

«

«

For SI units: 1000 British thermal units per hour = 0.293 kW

2025 CALIFORNIA PLUMBING CODE 217

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

FUEL GAS PIPING

«

«

«

«

«

«

«

«

«

«

1208.5.4 Plastic Pipe, Tubing, and Fittings. Polyethylene plastic pipe, tubing, and fittings used to supply fuel gas shall conform to ASTM D2513. Pipe to be used shall be marked “gas” and “ASTM D2513.” Polyamide pipe, tubing, and fittings shall be identified in and conform to ASTM F2945. Pipe to be used shall be marked “gas” and “ASTM F2945.” Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) plastic pipe, tubing, and fittings shall not be used to supply fuel gas. [NFPA 54:5.5.4.1.1 – 5.5.4.1.3]

1208.5.5 Regulator Vent Piping. Plastic pipe and fittings used to connect regulator vents to remote vent terminations shall be PVC (Schedule 40 and 80). PVC vent piping shall not be installed indoors. {NFPA 54:5.5.4.2}
California Plumbing Code High 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 § 413.0 High relevance — show source text
413.0 Flushing Devices . . . . . . . . . . . . . .65

413.1 Where Required . . . . . . . . . . . . . . .65

413.2 Flushometer Valves . . . . . . . . . . . .65

413.3 Flush Tanks . . . . . . . . . . . . . . . . . .65

413.4 Water Supply for Flush Tanks . . . .65

413.5 Overflows in Flush Tanks . . . . . . . .65

414.0 Dishwashing Machines . . . . . . . . . .65

414.1 Application . . . . . . . . . . . . . . . . . . .65

414.2 Backflow Protection . . . . . . . . . . . .65

414.3 Drainage Connection . . . . . . . . . . .65

414.4 Lead Content . . . . . . . . . . . . . . . . .65

415.0 Drinking Fountains . . . . . . . . . . . . .65

415.1 Application . . . . . . . . . . . . . . . . . . .65

415.2 Drinking Fountain Alternatives . . . .66

415.3 Drainage Connection . . . . . . . . . . .66

415.4 Location . . . . . . . . . . . . . . . . . . . . .66

416.0 Emergency Eyewash and Shower Equipment . . . . . . . . . . . . .66

416.1 Application . . . . . . . . . . . . . . . . . . .66

416.2 Water Supply . . . . . . . . . . . . . . . . .66

416.3 Installation . . . . . . . . . . . . . . . . . . .66

416.4 Location . . . . . . . . . . . . . . . . . . . . .66

416.5 Drain . . . . . . . . . . . . . . . . . . . . . . . .66

417.0 Faucets and Fixture Fittings . . . . . .66

417.1 Application . . . . . . . . . . . . . . . . . . .66

417.2 Deck Mounted Bath/Shower

Valves . . . . . . . . . . . . . . . . . . . . . . .66

417.3 Handheld Showers . . . . . . . . . . . . .66

417.4 Faucets and Fixture Fittings with Hose Connected Outlets . . . . .66

417.5 Separate Controls for Hot and Cold Water . . . . . . . . . . . . . . .66

417.6 Low-Pressure Water Dispenser . . . .66

417.7 Head Shampoo Sink Faucets . . . . .66

417.8 Footbaths and Pedicure Baths . . . .66

418.0 Floor Drains . . . . . . . . . . . . . . . . . .66

418.1 Application . . . . . . . . . . . . . . . . . . .66

418.2 Strainer . . . . . . . . . . . . . . . . . . . . . .66

418.3 Location of Floor Drains . . . . . . . . .67

Frequently asked questions

Do I need to test the water heater itself for lead?

The code does not require a separate “water heater test” — it requires that the materials and components that contact potable water meet the weighted average 0.25% limit under § 604.2, as applied to water-heater assemblies via § 504.7. Verify manufacturer declarations, NSF/ANSI certifications, or material specs for the heater and its connections.

Are flexible connectors or water heater connectors treated differently?

Flexible water connectors must meet the applicable standards listed in Chapter 604 (e.g., § 604.5) and, if they contact potable water, their wetted surfaces count toward the 0.25% weighted average. Check the connector’s lead content spec and any referenced standards.

If I replace only the faucet downstream of a heater, do I need to re-evaluate lead compliance?

Yes — replacing a component that changes the wetted-surface mix can change the weighted average. Any potable component added or replaced should be checked so the system-wide weighted average remains ≤ 0.25%.

What about solder used when installing a water heater?

Solder and flux used in potable piping are limited to 0.2% lead under § 604.2; ensure solders/fluxes used during installation meet that limit.

Do large service valves have to meet the 0.25% limit?

Certain large devices (flush valves, fill valves, flushometer valves, tub fillers, shower valves, service saddles, or water distribution main gate valves that are 2 inches (50 mm) or larger) are excepted from the potable lead limit in § 604.2. Verify whether a specific device falls under these exceptions.

Ask about the CPC

Get cited, plain-English answers on the California Plumbing Code for your project — any code section, any scenario.

Start Free Trial

Related in the CPC

What pressure- and temperature-limiting devices are required?

What are the rules for TPR and vacuum relief devices?

Safety devices, relief valves & temperature controls

California Plumbing Code