CPC · California Plumbing Code

How are residential fire sprinkler systems covered under water distribution rules?

For a homeowner: the CPC says residential sprinklers are handled by Chapter 6 and must be installed per the Residential Code or Fire Code. If your home sprinkler is a multipurpose system that follows R309/NFPA‑13D (potable‑rated piping, no antifreeze, no fire department connection), you typically do NOT need a backflow preventer at the service — but you must follow R309 requirements (materials, valves, inspections, owner sign).

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Last reviewed: July 6, 2026

What the code requires — plain English

Residential automatic sprinkler systems are regulated as part of the water supply and distribution rules in Chapter 6 of the California Plumbing Code. The CPC explicitly calls out residential fire sprinkler systems in § 612.0 and says their installation must comply with the California Residential Code or the California Fire Code per § 612.1.

The single most important rule: If a residential sprinkler system is installed as part of the potable water distribution (a “multipurpose” system), it may be permitted to remain connected to the domestic water system without additional backflow protection — but only when it meets the specific conditions in the Residential Code (NFPA 13D / Section R309) such as using potable‑suitable piping, having no antifreeze, and having no fire department connection.

Requirements in detail

Controlling CPC sections

  • § 612.0 — Residential Fire Sprinkler Systems: identifies residential sprinklers as addressed in Chapter 6 (water supply & distribution).
  • § 612.1 — Installation: requires installation in compliance with the California Residential Code (Section R309 / NFPA 13D equivalency) or the California Fire Code.

Key decision dimensions (summary table)

Decision dimension What to check Code reference
System type Is system multipurpose (serves domestic fixtures and sprinklers) or stand‑alone (sprinkler piping isolated from domestic)? § 612.1; R309.3 (Residential Code)
Backflow requirement Is a backflow preventer required at the service connection? Not required when system meets R309.3.1.1 conditions (NFPA 13D or Section R309, potable‑suitable materials, no antifreeze, no FDC). If not meeting those, follow Fire Code / NFPA rules and CPC backflow rules. R309.3.1.1 (Residential Code) and CPC Chapter 6 guidance
Fire department connection (FDC) Presence of a FDC generally changes the requirement — systems with FDCs or non‑potable ties typically require backflow protection and other Fire Code provisions. Fire Code §903.3.5 and related (water supplies)
Piping materials Sprinkler piping that is part of the potable system must be made of materials suitable for potable water (listing/approval required). Nonmetallic piping must be listed for sprinkler use and may need protection. R309.3.1.1; R309.3.3 / nonmetallic rules (Residential Code)
Valving / isolation Valves that would isolate one or more sprinklers are prohibited except for an approved main or a single master control valve locked open. R309.3.3.2 (Residential Code)
Required inspections / sign Owner manual, warning sign at main shutoff, pre‑concealment inspection items are required by the Residential Code. R309.3.7; R309.3.8.1 (Residential Code)

(See the citations in each row for the authoritative text.)

How the CPC and Residential Code divide responsibilities

  • The CPC (Chapter 6) recognizes residential sprinkler systems as part of water distribution and points the installer/designer to the Residential Code or Fire Code for the specific sprinkler installation rules (§ 612.0 / § 612.1) rather than re‑stating NFPA technical design details.
  • The Residential Code (Section R309 / NFPA 13D equivalency) contains the operative provisions about when sprinklers can be multipurpose, when backflow protection is not required, piping material suitability, valve placement, inspection items, and other residential specifics.

Exceptions & special cases

  • No backflow preventer required at the service connection if ALL of these are true: system complies with NFPA 13D or Section R309, piping materials are suitable for potable water, and the system does not contain antifreeze or a fire department connection. (See R309.3.1.1.)
  • Chapter 6 of the CPC notes that where sprinkler systems are installed as part of the water distribution system and are not provided with a fire department connection, backflow protection for the water supply is not required — provided the other conditions are met. (This is the CPC’s statement of intent; detailed conditions are in R309.)
  • If the sprinkler system has a fire department connection, uses antifreeze, is connected to a nonpotable source, or uses materials not approved for potable water contact, then backflow protection and Fire Code/NFPA requirements apply (and the CPC/Fire Code reference those protections).

If a provision or design detail appears in NFPA 13/13D but is not printed in the CPC/Residential excerpts we have, that NFPA rule still governs by reference — but the exact NFPA text is not reproduced here. (I did not retrieve the NFPA text in the supplied files.)

Common mistakes

  • Installing shutoff valves that can isolate part of the sprinkler system (forbidden except for the entire system shutoff or a supervised master valve). Check R309.3.3.2.
  • Assuming any sprinkler‑to‑domestic connection is automatically allowed: the system must meet the R309/NFPA13D conditions (potable‑suitable materials, no antifreeze, no FDC) to avoid backflow devices. See R309.3.1.1 and § 612.1.
  • Omitting the required owner warning sign at the main shutoff (the Residential Code requires a sign explaining that the water system supplies fire sprinklers and warning against adding flow‑restricting devices without a fire‑protection review). See R309.3.7.
  • Using non‑listed plastic piping without required protection or listing for sprinkler service — nonmetallic piping must be listed for the application and may require protection where exposed. See R309.3.3.1 / 3.3.1.1.
  • Skipping the preconcealment inspection items required by R309.3.8.1 (e.g., verifying sprinkler locations, correct pipe sizing, allowed pipe length).

Worked example — single‑family multipurpose sprinkler check (concrete)

Scenario: A one‑family dwelling will use a multipurpose wet‑pipe sprinkler system (sprinklers and domestic fixtures supplied from the same potable service). There is no fire department connection, no antifreeze, and the installer proposes CPVC listed for potable water and for sprinkler use.

Step 1 — Installation authority: CPC §612.1 requires the sprinkler be installed per the Residential Code; use Section R309 as the design standard. Verify compliance with R309/NFPA 13D.

Step 2 — Backflow: Because the system is multipurpose, has no FDC, uses potable‑suitable piping, and contains no antifreeze, R309.3.1.1 says a backflow preventer at the service connection is NOT required. (Result: no RP required at meter.)

Step 3 — Valves: Do not install a shutoff valve in a location that would isolate one or more sprinklers. You may only have the main system shutoff or a single master control valve that is locked in the open position. (Check R309.3.3.2.)

Step 4 — Owner info & inspections: Provide the owner’s manual and place the required warning tag at the main shutoff about devices that restrict flow/pressure (per R309.3.7). Complete the preconcealment inspection items in R309.3.8.1 before closing walls.

Numeric check example (pipe‑length rule): The Residential Code requires that the developed length between the service valve and the most remote sprinkler not exceed the maximum allowable length in the R309 tables or the lengths used in a hydraulic calculation (see R309.3.6.2 references). If your chosen pipe size and material result in a developed length of 120 ft but the applicable table allows only 100 ft for that size/material, you must ups‑ize the pipe or perform a hydraulic calculation. (The specific table values are in R309.3.6.2 tables; consult those tables during design.)

Related provisions (quick list)

  • § 612.0 — Residential Fire Sprinkler Systems (CPC).
  • § 612.1 — Installation; compliance with Residential Code or Fire Code (CPC).
  • R309.3 / R309.3.1.1 — Multipurpose vs stand‑alone rules; when backflow preventer is not required (Residential Code).
  • R309.3.3 — Sprinkler piping support, shutoff valve rules, single‑dwelling limits (Residential Code).
  • R309.3.7 — Owner instructions and warning sign at main shutoff (Residential Code).
  • R309.3.8.1 — Preconcealment inspection items (Residential Code).
  • Fire Code §903.3.5 — Water supplies for automatic sprinkler systems; domestic service and residential combination services; FDC and supply adjustments (California Fire Code).
  • CPC Chapter 6 overview — Chapter regulates water supply and distribution and recognizes residential sprinkler systems (California Plumbing Code introduction).

Code references

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

  • CPC § 903.3.2 High relevance — show source text

    [F] 903.3.2 Quick-response and residential sprinklers. Where automatic sprinkler systems are required by this code, quickresponse or residential automatic sprinklers shall be installed in all of the following areas in accordance with Section 903.3.1 and their listings:

    1. Throughout all spaces within a smoke compartment containing care recipient sleeping units in Group I-2 in accordance with this code.

    2. Reserved.

    3. Throughout all spaces within a smoke compartment containing treatment rooms in ambulatory care facilities.

    4. Dwelling units and sleeping units in Group R occupancies.

    5. Light-hazard occupancies as defined in NFPA 13.

    [F] 903.3.3 Obstructed locations. Automatic sprinklers shall be installed with regard to obstructions that will delay activation or obstruct the water distribution pattern and shall be in accordance with the applicable automatic sprinkler system standard that is being used. Automatic sprinklers shall be installed in or under covered kiosks, displays, booths, concession stands, or equipment that exceeds 4 feet (1219 mm) in width. Not less than a 3-foot (914 mm) clearance shall be maintained between automatic sprinklers and the top of piles of combustible fibers.

    Exception: Kitchen equipment under exhaust hoods protected with a fire-extinguishing system in accordance with Section 904.

    [F] 903.3.4 Actuation. Automatic sprinkler systems shall be automatically actuated unless specifically provided for in this code.

    [F] 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 the Health and Safety Code Section 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.

    [F] 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.

    [F] 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.

    [F] 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.

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

    [F] 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.

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

    [F] 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.

  • CPC § 903.3.2 High relevance — show source text

    903.3.2 Quick-response and residential sprinklers. Where automatic sprinkler systems are required by this code, quickresponse or residential automatic sprinklers shall be installed in all of the following areas in accordance with Section 903.3.1 and their listings:

    1. Throughout all spaces within a smoke compartment containing care recipient sleeping units in Group I-2 in accordance with the California Building Code .

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    FIRE PROTECTION AND LIFE SAFETY SYSTEMS

    1. Reserved.

    2. Throughout all spaces within a smoke compartment containing treatment rooms in ambulatory care facilities.

    3. Dwelling units and sleeping units in Group I-1 and R occupancies.

    4. Light-hazard occupancies as defined in NFPA 13.

    903.3.3 Obstructed locations. Automatic sprinklers shall be installed with regard to obstructions that will delay activation or obstruct the water distribution pattern and shall be in accordance with the applicable automatic sprinkler system standard that is being used. Automatic sprinklers shall be installed in or under covered kiosks, displays, booths, concession stands or equipment that exceeds 4 feet (1219 mm) in width. Not less than a 3-foot (914 mm) clearance shall be maintained between automatic sprinklers and the top of piles of combustible fibers.

    Exception: Kitchen equipment under exhaust hoods protected with a fire-extinguishing system in accordance with Section 904.

    903.3.4 Actuation. Automatic sprinkler systems shall be automatically actuated unless specifically provided for in this code.

    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.

  • CPC § 3.2.4.2.2 High relevance — show source text

    R309.3.2.4.2.2 Additional requirements for side-wall sprinklers. Sidewall sprinklers within 5 feet (1524 mm) of the center of a ceiling fan, surface-mounted ceiling luminaire or similar object shall be considered to be obstructed, and additional sprinklers shall be installed.

    R309.3.2.5 Sprinkler installation on systems assembled with solvent cement. The solvent cementing of threaded adapter fittings shall be completed and threaded adapters for sprinklers shall be verified as being clear of excess cement prior to the installation of sprinklers on systems assembled with solvent cement.

    R309.3.2.6 Sprinkler modifications prohibited. Painting, caulking or modifying of sprinklers shall be prohibited. Sprinklers that have been painted, caulked, modified or damaged shall be replaced with new sprinklers.

    R309.3.3 Sprinkler piping system. Sprinkler piping shall be supported in accordance with requirements for cold water distribution piping. Sprinkler piping shall comply with the requirements for cold water distribution piping. For multipurpose piping systems, the sprinkler piping shall connect to and be a part of the cold water distribution piping system.

    Exception: For plastic piping, it shall be permissible to follow the manufacturer’s installation instructions.

    R309.3.3.1 Nonmetallic pipe and tubing. Nonmetallic pipe and tubing, such as CPVC, PEX, and PE-RT shall be listed for use in residential automatic sprinkler systems.

    R309.3.3.1.1 Nonmetallic pipe protection. Nonmetallic pipe and tubing systems shall be protected from exposure to the living space by a layer of not less than [3] / 8 -inch-thick (9.5 mm) gypsum wallboard, [1] / 2 -inch-thick (13 mm) plywood, or other material having a 15-minute fire rating.

    Exceptions:

    1. Pipe protection shall not be required in areas that do not require protection with sprinklers as specified in Section R309.3.1.2 .

    2. Pipe protection shall not be required where exposed piping is permitted by the pipe listing .

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    BUILDING PLANNING

    R309.3.3.2 Shutoff valves prohibited. With the exception of shutoff valves for the entire water distribution system or a single master control valve for the automatic sprinkler system that is locked in the open position, valves shall not be installed in any location where the valve would isolate piping serving one or more sprinklers.

    R309.3.3.3 Single dwelling limit. Piping beyond the service valve located at the beginning of the water distribution system shall not serve more than one dwelling.

    R309.3.3.4 Drain. A means to drain the automatic sprinkler system shall be provided on the system side of the water distribution shutoff valve.

    R309.3.4 Determining system design flow. The flow for sizing the sprinkler piping system shall be based on Sections R309.3.4.1 and R309.3.4.2

  • CPC § 3108F.6.4 High relevance — show source text

    Connections shall be installed at a safe access distance from the_ sumps, manifolds and loading arms (N/E).

    3108F.6.4 Foam supply (N/E). Product flammability, foam type, water flow rates and application duration shall be considered in foam supply calculations.

    Fixed foam proportioning equipment shall be located at a distance of at least 100 ft from the sumps, manifolds and loading arms, except where hydraulic limits of the foam delivery system require closer proximity.

    MOTs shall have a program to ensure that foam is replaced according to the manufacturer’s recommendations.

    3108F.6.5 Fire monitor systems. Fire monitors shall be located to provide coverage of MOT cargo manifolds, loading arms, hoses and vessel manifold areas. This coverage shall provide at least two independent streams of water/foam. Monitors shall be located to provide an unobstructed path between the monitor and the target area (N/E).

    If the vessel manifold is more than 30 ft above the wharf deck, the following factors shall be considered, in order to determine if monitors located on elevated masts or towers are required (N/E):

    1. Maximum tanker freeboard

    2. Tidal variations

    3. Pier/wharf/loading platform elevation

    4. Winds

    5. Fire water line pressure

    Sprinklers and/or remotely controlled water/foam monitors shall be installed to protect personnel, escape routes, shelter loca- tions and the fire water system (N).

    Isolation valves shall be installed in the fire water and the foam lines in order to segregate damaged sections without disabling the entire system. Readily accessible isolation valves shall be installed 100–150 ft from the manifold and the loading arm/hose area (N).

    3108F.6.6 Supplemental fire suppression systems (E). A supplemental system is an external waterborne or land- based source providing suppressant and equipment. Supplemental systems may not provide more than one-quarter of the total water require- ments specified in the Fire Protection Assessment.

    Additionally, supplementary systems shall not be considered in a Fire Protection Assessment, unless available within 20 minutes following the initiation of a fire alarm. Mutual aid may be considered as part of the supplemental system.

    3108F.7 Fire systems seismic assessment (N/E). Fire detection and protection systems, and emergency shutdown systems shall have a seismic assessment per Section 3104F.5. For strength evaluation of supports and attachments, see Section 3107F.7.

    For firewater piping and pipeline systems, see Section 3109F.7.

    3108F.8 References.

    [8.1] American Petroleum Institute (API), 2012, API Recommended Practice 2001 (API RP 2001), “Fire Protection in Refineries,” 9th ed., Washington, D.C.

    [8.2] International Chamber of Shipping (ICS), Oil Companies International Marine Forum (OCIMF), International Association of Ports and Harbors (IAPH), 2006, “International Safety Guide for Oil Tankers and Terminals (ISGOTT),” 5th ed., Witherby, London.

    [8.3] California Code of Regulations (CCR), Title 2, Division 3, Chapter 1, Article 5 – Marine Terminals Inspection and Monitoring (2 CCR 2300 et seq.)

  • CPC § 29-1 High relevance — show source text

    Using Equation 29-1, calculate the pressure available to offset friction loss in water-distribution piping between the service valve and the sprinklers.

    Step 8—Determine the maximum allowable pipe length

    Use Tables R309.3.6.2 (4) through R309.3.6.2 (9) to select a material and size for water distribution piping. The piping material and size shall be acceptable if the developed length of pipe between the service valve and the most remote sprinkler does not exceed the maximum allowable length specified by the applicable table. Interpolation of P t between the tabular values shall be permitted.

    The maximum allowable length of piping in Tables R309.3.6.2 (4) through R309.3.6.2 (9) incorporates an adjustment for pipe fittings. Additional consideration of friction losses associated with pipe fittings shall not be required.

    R309.3.7 Instructions and signs. An owner’s manual for the automatic sprinkler system shall be provided to the owner. A sign or valve tag shall be installed at the main shutoff valve to the water distribution system stating, “Warning, the water system for this home supplies fire sprinklers that require certain flows and pressures to fight a fire. Devices that restrict the flow or decrease the pressure or automatically shut off the water to the fire sprinkler system, such as water softeners, filtration systems and automatic shutoff valves, shall not be added to this system without a review of the fire sprinkler system by a fire protection specialist. Do not remove this sign.”

    R309.3.8 Inspections. The water distribution system shall be inspected in accordance with Sections R309.3.8.1 and R309.3.8.2.

    R309.3.8.1 Preconcealment inspection. The following items shall be verified prior to the concealment of any automatic sprinkler system piping:

    1. Sprinklers are installed in all areas as required by Section R309.3.1.1.
    2. Where sprinkler water spray patterns are obstructed by construction features, luminaires or ceiling fans, additional sprinklers are installed as required by Section R309.3.2.4.2.
    3. Sprinklers are the correct temperature rating and are installed at or beyond the required separation distances from heat sources as required by Sections R309.3.2.1 and R309.3.2.2 .
    4. The pipe size equals or exceeds the size used in applying Tables R309.3.6.2 (4) through R309.3.6.2 (9) or, if the piping system was hydraulically calculated in accordance with Section R309.3.6.1, the size used in the hydraulic calculation.
    5. The pipe length does not exceed the length permitted by Tables R309.3.6.2 (4) through R309.3.6.2 (9) or, if the piping system was hydraulically calculated in accordance with Section R309.3.6.1, pipe lengths and fittings do not exceed those used in the hydraulic calculation.

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    BUILDING PLANNING

  • California Plumbing Code High relevance — show source text

    0
    156
    145
    136
    129|306
    281
    262
    245
    232|482
    443
    413
    387
    366|1000
    924
    859
    806
    761| |125
    150
    175
    200
    250|125
    150
    175
    200
    250|NA
    NA
    NA
    NA
    NA|11
    10
    NA
    NA
    NA|22
    20
    18
    17
    15|38
    34
    31
    29
    26|53
    48
    45
    41
    37|114
    103
    95
    89
    78|206
    186
    171
    159
    141|324
    294
    270
    251
    223|675
    612
    563
    523
    464| |300
    350
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    450
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    350
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    500|NA
    NA
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    NA
    NA|NA
    NA
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    NA|13
    12
    11
    11
    10|23
    22
    20
    19
    18|33
    31
    28
    27
    25|71
    65
    61
    57
    54|128
    118
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    103
    97|202
    186
    173
    162
    153|420
    387
    360
    338
    319| |550
    600
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    7

  • CPC § 1-2016 High relevance — show source text
    Col1 STANDARDS, PUBLICATIONS, PRACTICES, AND GUIDES Col3
    DOCUMENT NUMBER DOCUMENT TITLE APPLICATION
    AHAM AHAM AHAM
    AHAM FWD-1-2016 Food Waste Disposers Appliances
    ARCSA ARCSA ARCSA
    ARCSA/ASPE 78-2015 Stormwater Harvesting System Design for Direct End-Use Applications Miscellaneous
    ASABE ASABE ASABE
    ASABE/ICC 802-2014 Landscape Irrigation Sprinkler and Emitter Standard Irrigation
    ASCE ASCE ASCE
    ASCE 25-2016 Earthquake-Actuated Automatic Gas Shutoff Devices Fuel Gas
    ASHRAE ASHRAE ASHRAE
    ASHRAE/IES 90.1-2019 Energy Standard for Buildings Except Low-Rise Residential Buildings Miscellaneous
    ASHRAE/IES 90.2-2018 Energy-Efficient Design of Low-Rise Residential Buildings Miscellaneous
    ASHRAE 188-2021 Legionellosis: Risk Management for Building Water Systems Risk Management
    ASHRAE Guideline 12-
    2020    		 Managing the Risk of Legionellosis Associated with Building Water Systems Risk Management
    ASME ASME ASME
    ASME A13.1-2020 Scheme for the Identification of Piping Systems Piping
    ASME A112.4.3-1999
    (R2019)    		 Plastic Fittings for Connecting Water Closets to the Sanitary Drainage System Fittings
    ASME A112.19.10-2017 Retrofit Dual Flush Devices for Water Closets Fixtures
    ASME A112.21.3M-1985
    (R2017)    		 Hydrants for Utility and Maintenance Use Valves
    ASME B1.20.3-1976
    (R2018)    		 Dryseal Pipe Threads (Inch) Joints
    ASME B16.39-2019 Malleable Iron Threaded Pipe Unions: Classes 150, 250 and 300 Fittings
    ASME B16.40-2019 Manually Operated Thermoplastic Gas Shutoffs and Valves in Gas Distribution Sys-
    tems    		 Valves
    ASME B31.1-2020 Power Piping Piping
    ASME B36.19M-2018 Stainless Steel Pipe Piping, Ferrous
    ASME BPVC Section IV-
    2021    		 Rules for Construction of Heating Boilers Miscellaneous
    ASPE ASPE ASPE
    ARCSA/ASPE 78-2015 Stormwater Harvesting System Design for Direct End-Use Applications Miscellaneous
    WQA/ASPE/ANSI S-803-
    2017    		 Sustainable Drinking Water Treatment Systems Miscellaneous
    ASSE ASSE ASSE
    ASSE 1017-2009 Temperature Actuated Mixing Valves for Hot Water Distribution Systems Valves
    ASSE 1066-1997 Individual Pressure Balancing In-Line Valves for Individual Fixture Fittings Valves
    ASSE
  • CPC § 11B-89 High relevance — show source text

    11B-606 Lavatories and Sinks. . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-89

    11B-607 Bathtubs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-90

    11B-608 Shower Compartments . . . . . . . . . . . . . . . . . . . . . . . . .11B-92

    11B-609 Grab Bars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-96

    11B-610 Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-97

    11B-611 Washing Machines and Clothes Dryers. . . . . . . . . . .11B-98

    11B-612 Saunas and Steam Rooms . . . . . . . . . . . . . . . . . . . . . .11B-99

    DIVISION 7 – COMMUNICATION ELEMENTS AND

    FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11B-100

    11B-701 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-100

    11B-702 Fire Alarm Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-100

    11B-703 Signs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-100

    11B-704 Telephones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-107

    11B-705 Detectable Warnings and Detectable Directional

    Texture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-108

    11B-706 Assistive Listening Systems. . . . . . . . . . . . . . . . . . . . .11B-110

    11B-707 Automatic Teller Machines, Fare Machines and Point-of-Sale Devices . . . . . . . . . . . . . . . . . . . .11B-111

    11B-708 Two-Way Communication Systems. . . . . . . . . . . . .11B-112

    DIVISION 8 – SPECIAL ROOMS, SPACES AND ELEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11B-114

  • CPC § 11B-73 Medium relevance — show source text

    11B-502 Parking Spaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-73

    11B-503 Passenger Drop-Off and Loading Zones . . . . . . . . .11B-76

    11B-504 Stairways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-77

    11B-505 Handrails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-78

    DIVISION 6 – PLUMBING ELEMENTS AND FACILITIES. . . . 11B-81

    11B-601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-81

    11B-602 Drinking Fountains and Bottle-Filling Stations . . .11B-81

    11B-603 Toilet and Bathing Rooms . . . . . . . . . . . . . . . . . . . . . .11B-81

    11B-604 Water Closets and Toilet Compartments. . . . . . . . .11B-82

    11B-605 Urinals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-88

    11B-606 Lavatories and Sinks. . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-89

    11B-607 Bathtubs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-90

    11B-608 Shower Compartments . . . . . . . . . . . . . . . . . . . . . . . . .11B-92

    11B-609 Grab Bars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-96

    11B-610 Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11B-97

    11B-611 Washing Machines and Clothes Dryers. . . . . . . . . . .11B-98

    11B-612 Saunas and Steam Rooms . . . . . . . . . . . . . . . . . . . . . .11B-99

    DIVISION 7 – COMMUNICATION ELEMENTS AND

    FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11B-100

  • CPC § 611.1 Medium relevance — show source text

    WATER SUPPLY AND DISTRIBUTION

    Col1 TABLE 611.1 DRINKING WATER TREATMENT UNITS Col3 Col4
    APPLICATION RESIDENTIAL RESIDENTIAL COMMERCIAL
    APPLICATION POINT OF USE POINT OF ENTRY POINT OF ENTRY
    Aesthetic Contaminant
    Reduction (filters)    		 NSF/ANSI 42 NSF/ANSI 42 ASSE 1087 and NSF/ANSI 42*
    Health Related Contaminant
    Reduction (filters)    		 NSF/ANSI 53 NSF/ANSI 53 ASSE 1087 and NSF/ANSI 53*
    Water Softener – NSF/ANSI 44 ASSE 1087
    Ultraviolet Water Treatment NSF/ANSI 55 NSF/ANSI 55 ASSE 1087
    Reverse Osmosis NSF/ANSI 58 NSF/ANSI/CAN 61 ASSE 1087
    Distillation NSF/ANSI 62 NSF/ANSI 62 ASSE 1087 
     - Required for commercial modular systems only.

    TABLE 611.4 SIZING OF RESIDENTIAL WATER SOFTENERS [4]

    REQUIRED SIZE OF
    SOFTENER CONNECTION
    (inches)    		 NUMBER OF BATHROOM
    GROUPS SERVED1

    3⁄4    		 up to 22


    1    		 up to 43

    For SI units: 1 inch = 25 mm

    Notes: 1 Installation of a kitchen sink and dishwasher, laundry sink, and automatic clothes washer permitted without additional size increase. 2 An additional water closet and lavatory permitted. 3 Over four bathroom groups, the softener size shall be engineered for the specific installation. 4 See also Appendix A, Recommended Rules for Sizing the Water Supply System, and Appendix C, Alternate Plumbing Systems, for alternate methods of sizing water supply systems.

    613.0 Domestic Hot-Water Distribution Systems for Health Facilities and Clinics. [OSHPD 1, 2, 3, 4 & 5]

    613.1 The domestic water-heating equipment and distribu- tion systems shall supply water at the temperature and amounts shown in Table 613.1. Where the system is designed by a mechanical engineer, appropriate diversity factors may be utilized.

    TABLE 613.1

    [OSHPD 1, 2, 3, 4 & 5] HOT WATER USE

    Col1 CLINICAL DIETARY1 LAUNDRY2

    Liter/Hour/Bed    		 11.9 7.2 7.6

    Gallons/Hour/Bed    		 3 2 2


    Temperature °C    		 41-49.0 49.03 71.0


    Temperature °F    		 105-120.0 120.03 160.0

    1 Rinse water temperature at warewasher or potsinks shall be 180°F (82°C) unless a chemical disinfection is provided.

  • CPC § 2025 Medium relevance — show source text

    Appendix A Recommended Rules for Sizing the Water Supply System.

    Appendix A provides a method of sizing the water supply and distribution system that provides precise calculations to establish the proper pressures and flow to the system’s fixtures. The goal of sizing the system is to deliver an acceptable volume of water to the most hydraulically remote fixture during minimum pressure and maximum flow conditions; provide satisfactory water pressure to the most hydraulically remote fixture during minimum pressure and maximum flow conditions; and to prevent excessive water velocity during maximum flow conditions.

    Appendix B Explanatory Notes on Combination Waste and Vent Systems.

    Appendix B contains general guidelines for the design and installation of combination waste and vent systems. These systems are designed for waste piping and are purposely oversized to serve as both a waste and vent pipe to avoid excessive pneumatic effects at fixture drains.

    Appendix C Alternate Plumbing Systems.

    The intent of this appendix is to provide clarification of procedures for the design and approval of engineered plumbing systems, alternate materials, and equipment that are not specifically covered in other parts of the code. Alternative methods are allowed to be used where approved by the authority having jurisdiction. Approval of alternatives is based on a demonstration showing that the method or material used is at least equivalent in strength, deflection, and capacity to that provided by the prescriptive methods and materials.

    Appendix D Sizing Storm Water Drainage Systems.

    Appendix D provides general guidelines for the sizing of stormwater drainage systems. There are two pieces of information that must always be a given. They are the roof size and the rate of rainfall for the area.

    2025 CALIFORNIA PLUMBING CODE xvii

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

    FORMAT OF THE UNIFORM PLUMBING CODE

    Appendix E Manufactured/Mobile Home Parks and Recreational Vehicle Parks.

    The provisions of this appendix apply to the plumbing and drainage systems of mobile home and recreational vehicle parks. These provisions also apply to the use, maintenance, and installation for supplying fuel gas, water, electricity, and disposal of sewage from accessory buildings or structures, and building components.

    Appendix F Firefighter Breathing Air Replenishment Systems.

    Appendix F provides guidance on installing firefighter breathing air replenishment systems. System components include outside fire department connection panel, interior air fill panel or station, interconnected piping distribution system and pressure monitoring switch. Fire departments access the system through an outside connection panel and are able to pump air into the system. The firefighters inside the structure access the system at fill stations that are found throughout the building. The piping distribution system is made from stainless tubing or other approved materials. It delivers compressed air to the building’s interior air-fill stations and interior air-fill panels. The tubing also acts as a conduit in the interior of the building between the outside connection panel and the air storage system. If the system becomes over-pressurized, the air monitoring system also acts as a pressure relief. A system isolation valve is placed alongside each interior air fill station and interior air fill panel to isolate the system.

    Appendix G Sizing of Venting Systems.

    Appendix G provides added information on the sizing of gas vents. This appendix is useful to the end user for the proper sizing of venting systems. A series of examples are given that show how to use the tables and other requirements of Chapter 5.

    Appendix H Private Sewage Disposal Systems.

  • CPC § 1-8.1 Medium relevance — show source text
    INSULATING MATERIALSm—continued Col2 Col3 Col4 Col5 Col6 Col7
    ** STRUCTURAL**
    PARTS TO BE
    PROTECTED    		 ** ITEM**
    NUMBER    		 ** INSULATING MATERIAL USED** ** MINIMUM THICKNESS OF INSULATING MATERIAL**
    FOR THE FOLLOWING FIRE-RESISTANCE PERIODS
    (inches)    		 ** MINIMUM THICKNESS OF INSULATING MATERIAL**
    FOR THE FOLLOWING FIRE-RESISTANCE PERIODS
    (inches)    		 ** MINIMUM THICKNESS OF INSULATING MATERIAL**
    FOR THE FOLLOWING FIRE-RESISTANCE PERIODS
    (inches)    		 ** MINIMUM THICKNESS OF INSULATING MATERIAL**
    FOR THE FOLLOWING FIRE-RESISTANCE PERIODS
    (inches)
    ** STRUCTURAL**
    PARTS TO BE
    PROTECTED    		 ** ITEM**
    NUMBER    		 ** INSULATING MATERIAL USED** ** 4 hours** ** 3 hours** ** 2 hours** ** 1 hour**
    1. Steel columns
    and all of
    primary
    trusses—
    continued    		 1-8.1 Wood-fibered gypsum plaster mixed 1:1 by weight gypsum-
    to-sand aggregate applied over metal lath. Lath lapped 1"
    and tied 6" on center at all end, edges and spacers with
    0.049" (No. 18 B.W. gage) steel tie wires. Lath applied over1/2"
    spacers made of3/ 4" furring channel with 2" legs bent around
    each corner. Spacers located 1" from top and bottom of
    member and not greater than 40" on center and wire tied
    with a single strand of 0.049" (No. 18 B.W. gage) steel tie
    wires. Corner bead tied to the lath at 6" on center along each
    corner to provide plaster thickness.    		 — — 15/8 —
    1. Steel columns
    and all of
    primary
    trusses—
    continued    		 1-9.1 Minimum W8x35 wide flange steel column (w/d ≥ 0.75) with
    each web cavity filled even with the flange tip with normal
    weight carbonate or siliceous aggregate concrete (3,000 psi
    minimum compressive strength with 145 pcf ± 3 pcf unit
    weight). Reinforce the concrete in each web cavity with a
    minimum No. 4 deformed reinforcing bar installed vertically
    and centered in the cavity, and secured to the column web
    with a minimum No. 2 horizontal deformed reinforcing bar
    welded to the web every 18" on center vertically. As an alter-
    native to the No. 4 rebar,3/4" diameter by 3" long headed
    studs, spaced at 12" on center vertically, shall be welded on
    each side of the web mid-way between the column flanges.    		 — — — See
    Note n
    2.

Frequently asked questions

Do residential sprinkler systems always need a backflow preventer at the water service?

Not always. If the system is a multipurpose potable system that meets R309.3.1.1 (complies with NFPA 13D or R309, uses potable‑suitable piping, contains no antifreeze, and has no fire department connection), a backflow preventer at the service is not required. Otherwise backflow protection per Fire Code/NFPA/CPC applies.

Can the sprinkler piping also supply domestic fixtures?

Yes — a multipurpose system is allowed under the Residential Code when designed and installed per R309 (equivalent to NFPA 13D). Confirm piping materials, absence of antifreeze, and other R309 conditions.

If I add a fire department connection (FDC), what changes?

Adding an FDC generally removes the “no‑backflow” exception: systems with FDCs are treated under the Fire Code and NFPA rules and typically require backflow protection and additional hydraulic/fire service considerations. See Fire Code §903.3.5.

Are plastic pipes allowed for residential sprinklers?

Yes if the plastic (CPVC, PEX, PE‑RT, etc.) is listed for use in residential automatic sprinkler systems and any required protection (e.g., covering where called for) is provided per R309.3.3.1 and related text.

What inspections are required before concealing sprinkler piping?

Preconcealment inspection must verify sprinkler locations, obstruction adjustments, correct temperature‑rating and separation, correct pipe size used in tables or hydraulic calculations, and allowable pipe length per R309.3.8.1.

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