Title 24 · California Energy Code
What manufacturer certification is required for service water-heating systems?
Before installing a commercial or nonresidential water‑heating system in California, you must obtain the manufacturer’s certification that the product meets every applicable requirement of Section § 110.3 (controls, efficiency, installation). Appliances in the Title 20 scope must also be listed by the California Energy Commission; other systems require a signed manufacturer declaration or Commission‑approved evidence.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Any service water‑heating system or equipment may be installed only if the manufacturer has certified that the product complies with all requirements of Section § 110.3(a) for that system or equipment. This includes requirements for temperature controls, efficiency, and installation (outlet controls, insulation, recirculation, etc.) as specified throughout § 110.3. The certification pathway differs for appliances subject to the Appliance Efficiency Regulations versus other systems: appliances in the scope of Title 20 must be certified to the Energy Commission; other systems require a manufacturer’s declaration under penalty of perjury and traceable evidence of certification.
The single controlling rule: a service water‑heating product cannot be installed in California unless the manufacturer certifies it meets every requirement of Section § 110.3 for that product.
Requirements in detail
Scope of the manufacturer certification
- The manufacturer must assert that the system or equipment complies with all applicable requirements of § 110.3 before installation is allowed. § 110.3(a) is the controlling clause requiring that certification.
- If the product is an appliance within the scope of the Appliance Efficiency Regulations (Title 20, § 1601), that appliance must be certified to the Energy Commission per Title 20 procedures (i.e., listed in the Commission’s database) rather than only a manufacturer declaration. See § 110.0(b)1 and related appliance rules.
What the certification must cover
- Temperature controls: Manufacturer must certify that systems have automatic temperature controls adjustable across the acceptable range in the ASHRAE Handbook (Table 3, Ch. 50) — except for residential occupancies, which are an explicit exception to § 110.3(a)1.
- Efficiency: Equipment must meet Appliance Efficiency Regulations as required by § 110.3(b); if multiple standards or test methods apply, the equipment must meet each listed standard and applicable test(s).
- Installation requirements: Manufacturer certification supports that the product can be installed in compliance with the installation subsections of § 110.3(c) (including outlet temperature controls, distribution controls, tank insulation, recirculation loop rules, etc.).
Decision‑relevant dimensions (table)
| Decision dimension / threshold | What the code requires | Code Reference |
|---|---|---|
| Manufacturer certification required prior to installation | Manufacturer must certify the product complies with all applicable § 110.3 requirements | § 110.3(a) |
| Appliance subject to Title 20 (Appliance Efficiency Regulations) | Must be certified to the Energy Commission (listed in Commission database) | § 110.0(b)1 and § 110.1(a) |
| Temperature controls (automatic, adjustable across range) | Required for service water‑heating systems (except residential) | § 110.3(a)1 |
| Outlet temperature boosters / remote heaters threshold | If total system capacity > 167,000 Btu/hr, outlets needing higher temps must have separate boosters/heat exchangers | § 110.3(c)1 |
| Instantaneous water heater isolation valves threshold | Instantaneous WH with input > 6.8 kBtu/hr (2 kW) must have isolation valves on cold and hot lines and fittings for flushing | § 110.3(c)6 |
| Unfired storage tank insulation | External insulation ≥ R‑3.5, OR internal + external combined ≥ R‑16, OR surface heat loss < 6.5 Btu/hr·ft² (80°F ΔT) | § 110.3(c)3 A–C |
| HPWH backup heat and ventilation | Air‑source HPWHs: backup heat required in some conditions; ventilation/space sizing per manufacturer or specific NFA requirements — see § subparts | § 110.3(c)7 A–B |
| Certification evidence acceptable forms | Commission directory listing, copy of application + letter of acceptance, confirmation from directory publisher, or Commission‑approved label | § 110.0(b)3 |
How manufacturers must document certification
- For appliances covered by Title 20 (Appliance Efficiency Regulations), certification is performed to the Energy Commission and listed in its database. § 110.0(b)1 requires use of that database for verification.
- For other systems required to be certified to the Commission, the manufacturer must provide a declaration executed under penalty of perjury stating completeness and correct testing per Part 6 test procedures where applicable. Acceptable verification is a Commission directory listing, application + acceptance letter, publisher confirmation, or Commission‑approved label. § 110.0(b)2–3 document these rules.
Exceptions & special cases
- Residential exception for temperature controls: The automatic adjustable temperature control requirement in § 110.3(a)1 does not apply to residential occupancies.
- Plumbing Code override for certain outlets: Systems covered by California Plumbing Code § 613.0 follow that plumbing section instead of § 110.3(c)1 for outlet temperature controls.
- State buildings: Newly constructed state buildings must use systems that provide at least 60% of service water heating energy from site solar or recovered energy, with an exception if the State Architect finds it infeasible. This is an installation/selection requirement that the manufacturer’s certification must support. § 110.3(c)5 (and related Appendix text) applies.
- Title 20 vs Part 6 certification paths: If a product is within Title 20 (appliance) it must follow Title 20 certification; other systems follow Part 6 manufacturer declaration and Commission listing rules. Verify which path applies before accepting manufacturer certification.
Common mistakes
- Assuming any manufacturer statement is sufficient — for appliances within the Title 20 scope you must confirm the item is listed in the Energy Commission’s certified appliance database (not just a label). § 110.0(b)1.
- Missing the 167,000 Btu/hr capacity threshold that triggers separate booster/heater requirements for outlets; treating every high‑temperature outlet the same regardless of system capacity. § 110.3(c)1.
- Overlooking the residential exception for temperature control rules in § 110.3(a)1. Designers sometimes apply the temperature‑control duty where the code excepts it.
- Confusing manufacturer declaration (Part 6) with an Energy Commission Title 20 listing — they are different compliance paths and have different verification evidence. § 110.0(b).
- Failing to verify tank insulation meets one of the three methods (external R‑value, combined R‑value, or heat loss) required by § 110.3(c)3.
Worked example — concrete scenario
Scenario: A hotel is specifying a new central service hot‑water system with total design capacity 200,000 Btu/hr and multiple outlets that require higher than “service water” temperature.
Step 1 — Manufacturer certification: The specified system must be installed only if the manufacturer certifies the system complies with all applicable requirements of § 110.3. Confirm the manufacturer’s declaration or Energy Commission listing as applicable. § 110.3(a) and § 110.0(b).
Step 2 — Outlet temperature boosters: Because total system capacity = 200,000 Btu/hr, which is greater than 167,000 Btu/hr, any outlets that require temperatures higher than standard service water must be supplied by separate remote heaters, heat exchangers or boosters. Designer must show the manufacturer’s certification covers this condition or provide compliant separate equipment. § 110.3(c)1.
Step 3 — Efficiency documentation: Confirm the equipment meets applicable Appliance Efficiency Regulations and that required efficiency testing was performed using the test procedures required by Part 6; if the device is a covered appliance, verify its Energy Commission listing. § 110.3(b) and § 110.1/§ 110.0(b).
Step 4 — Tank insulation and other installation items: If the system includes unfired storage tanks, ensure insulation meets one of the options (external R‑3.5, combined R‑16, or heat loss < 6.5 Btu/hr·ft²). Confirm manufacturer’s spec and certification state which path is used. § 110.3(c)3 A–C.
Step 5 — Certification evidence to keep in plan submittal: Provide either the Commission database listing (if Title 20), or the manufacturer’s signed declaration plus any acceptance letter/directory evidence referenced in § 110.0(b)3.
Related provisions
- § 110.0(b) — Certification requirements and acceptable forms of certification evidence (Energy Commission directory, application + acceptance, label).
- § 110.1 — Mandatory requirements for appliances and relation to Title 20 Appliance Efficiency Regulations (how to verify appliance conformance).
- § 110.3(b) — Equipment efficiency requirements and interaction with Appliance Efficiency Regulations.
- § 110.3(c) — Installation requirements for service water‑heating systems (outlet controls, insulation, recirculation, HPWH rules, etc.).
- California Plumbing Code § 613.0 — Alternate requirements that apply to certain outlet temperature controls (see exception to § 110.3(c)1).
Code references
Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:
§ 110.2 High relevance — show source text
Units that only have capabilities for partial heat recovery shall meet the requirements of Table 110.2-D, Water
Chilling Packages—Minimum Efficiency Requirements.
g. For heat recovery heating chilling package applications where there is simultaneous cooling and heating, compliance with the heating performance heat recover COPHR is
only required at one of the four heating AHRI 550/590 (I-P) standard ratings conditions of Low, Medium, Hot-Water 1 or Hot-Water 2. Compliance with the cooling-only perfor-
mance is required as defined in Notes b and c of Table 110.2-I.
h. Water-to-water heat pumps with a capacity less than 135,000 Btu/h are included in Table 110.2-B, Heat Pumps—Minimum Efficiency Requirements.
i. Source leaving liquid temperature.
1. The cooling evaporator liquid flow rate used for the heating rating for a reverse cycle air-to-water heat pump shall be the flow rate determined during the full-load cool-
ing rating.
2. The cooling evaporator liquid flow rate for the simultaneous cooling and heating and heat recovery liquid cooled chilling packages rating shall be the liquid flow rates
from the cooling operation full-load rating.
3. For heating-only fluid-to-fluid chiller packages, the evaporator flow rate obtained with an entering liquid temperature of 54°F and a leaving liquid temperature of 44°F
shall be used.
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ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS
SECTION 110.3—MANDATORY REQUIREMENTS FOR SERVICE WATER-HEATING SYSTEMS AND EQUIPMENT
(a) Certification by manufacturers. Any service water- heating system or equipment may be installed only if the manufacturer has certified that the system or equipment complies with all of the requirements of this subsection for that system or equipment.
- Temperature controls for service water-heating systems. Service water-heating systems shall be equipped with automatic temperature controls capable of adjustment from the lowest to the highest acceptable temperature settings for the intended use as listed in Table 3, Chapter 50 of the ASHRAE Handbook, HVAC Applications Volume or Table 613.1 of the Cali- fornia Plumbing Code for healthcare facilities. Exception to Section 110.3(a)1: Residential occupancies.
(b) Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section 110.1, subject to the following:
If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
Where equipment can serve more than one function, such as both heating and cooling, or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.
(c) Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment. 1.
§ 110.3 High relevance — show source text
SECTION 110.3—MANDATORY REQUIREMENTS FOR SERVICE WATER-HEATING SYSTEMS AND EQUIPMENT
(a) Certification by manufacturers. Any service water- heating system or equipment may be installed only if the manufacturer has certified that the system or equipment complies with all of the requirements of this subsection for that system or equipment.
- Temperature controls for service water-heating systems. Service water-heating systems shall be equipped with automatic temperature controls capable of adjustment from the lowest to the highest acceptable temperature settings for the intended use as listed in Table 3, Chapter 50 of the ASHRAE Handbook, HVAC Applications Volume or Table 613.1 of the Cali- fornia Plumbing Code for healthcare facilities. Exception to Section 110.3(a)1: Residential occupancies.
(b) Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section 110.1, subject to the following:
If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
Where equipment can serve more than one function, such as both heating and cooling, or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.
(c) Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.
- 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.
- 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.
- 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.
§ 100.1 High relevance — show source text
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ALL OCCUPANCIES—GENERAL PROVISIONS
FIGURE 100.1-A CALIFORNIA CLIMATE ZONES
Climate Zones for Residential and Nonresidential Occupancies
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2 ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE
MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS
SECTION 110.0—SYSTEMS AND EQUIPMENT—GENERAL
Sections 110.1 through 110.12 specify requirements for manufacturing, construction and installation of certain systems, equipment, appliances and building components that are installed in buildings within the scope of Section 100.0(a).
Note: The requirements of Sections 110.0 through 110.12 apply to newly constructed buildings. Sections 141.0 and 150.2 specify which requirements of Sections 110.1 through 110.12 also apply to additions and alterations to existing buildings.
(a) General Requirements. Systems, equipment, appliances and building components shall only be installed in a building within the scope of Section 100.0(a) regulated by Part 6 only if:
- The manufacturer has certified that the system, equipment, appliances or building component complies with the applicable manufacturing provisions of Sections 110.1 through 110.12; and
- The system, equipment, appliance or building component complies with all applicable installation provisions of Sections 110.1 through 110.12.
(b) Certification Requirements for Manufactured Systems, Equipment, Appliances and Building Components.
- Appliances that are within the scope of Section 1601 of the Appliance Efficiency Regulations shall only be installed if they have been certified to the Energy Commission by the manufacturer, pursuant to the provisions of Title 20 California Code of Regulations, Section 1606; or
- Systems, equipment, appliances and building components that are required by Part 6 or the Reference Appendices to be certified to the Energy Commission, which are not appliances that are within the scope of Section 1601 of the Appliance Efficiency Regulations, shall only be installed if they are certified by the manufacturer in a declaration, executed under penalty of perjury under the laws of the State of California, that: A. All the information provided pursuant to the certification is true, complete, accurate and in compliance with all applicable requirements of Part 6; and B. The equipment, product, or device was tested using the test procedure specified in Part 6 if applicable
- The certification status of any system, equipment, appliance or building component shall be confirmed only by reference to: A. A directory published or approved by the Commission; or B. A copy of the application for certification from the manufacturer and the letter of acceptance from the Commission staff; or C. Written confirmation from the publisher of a Commission-approved directory that a device has been certified; or D. A Commission-approved label on the device.
Note: Part 6 does not require a builder, designer, owner, operator, or enforcing agency to test any certified device to determine its compliance with minimum specifications or efficiencies adopted by the Commission.
§ 1-19 High relevance — show source text
The leakage rate shall be confirmed through field verification and diagnostic testing, in accordance with procedures set forth in the Reference Nonresidential Appendix NA1 of the California Energy Commission 2008 Building Energy Efficiency Stan- dards for Residential and Nonresidential Buildings.
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APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]
A6.207.2.6 Variable air volume control for single zone systems. Effective January 1, 2012, all unitary air conditioning equipment and air-handling units with mechanical cooling capacity at ARI conditions greater than or equal to 110,000 Btu/hr that serve single zones shall be designed for variable supply air volume with their supply fans controlled by two-speed motors, variable speed drives or equipment that has been demonstrated to the Executive Director to use no more energy. The supply fan controls shall modulate down to a minimum of [2] / 3 of the full fan speed or lower at low cooling demand.
A6.207.3 Service water-heating systems and equipment.
A6.207.3.1 Certification by manufacturers. Any service water-heating system or equipment may be installed only if the manufacturer has certified that the system or equipment complies with all of the requirements of this subsection for that system or equipment.
A6.207.3.1.1 Temperature controls for service water-heating systems. Service water-heating systems shall be equipped with automatic temperature controls capable of adjustment from the lowest to the highest acceptable temperature settings for the intended use as listed in Table 2, Chapter 9 of the ASHRAE Handbook, HVAC Applications Volume.
A6.207.3.2 Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section A6.210.1, subject to the following:
- If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
- If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
- Where equipment can serve more than one function, such as both heating and cooling or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
- Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.
A6.207.3.3 Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.
A6.207.3.3.1 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.
A6.207.3.3.2 Temperature controls for public lavatories. The controls shall limit the outlet temperature to 110°F.
§ 207.2.4.7 High relevance — show source text
- Heating hot water systems.
- Condenser water systems serving only water-cooled chillers.
A6.207.2.4.7 Hydronic heat pump (WLHP) controls. Hydronic heat pumps connected to a common heat pump water loop with central devices for heat rejection and heat addition shall have controls that are capable of providing a heat pump water supply temperature dead band of at least 20°F between initiation of heat rejection and heat addition by the central devices.
Exception: Where a system loop temperature optimization controller is used to determine the most efficient operating temperature based on real-time conditions of demand and capacity, dead bands of less than 20°F shall be allowed.
A6.207.2.5 Air distribution system duct leakage sealing. All duct systems shall be sealed to a leakage rate not to exceed 6 percent of the fan flow if the duct system:
A6.207.2.5.1 Is connected to a constant volume, single zone, air conditioners, heat pumps or furnaces; and
A6.207.2.5.2 Serves less than 5,000 square feet of floor area; and
A6.207.2.5.3 Has more than 25 percent duct surface area located in one or more of the following spaces:
Outdoors; or
In a space directly under a roof where the U -factor of the roof is greater than the U -factor of the ceiling; or Exception: Where the roof meets the requirements of Section 143(a)1C of Title 24, Part 6.
In a space directly under a roof with fixed vents or openings to the outside or unconditioned spaces; or
In an unconditioned crawlspace; or
In other unconditioned spaces.
The leakage rate shall be confirmed through field verification and diagnostic testing, in accordance with procedures set forth in the Reference Nonresidential Appendix NA1 of the California Energy Commission 2008 Building Energy Efficiency Stan- dards for Residential and Nonresidential Buildings.
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APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]
A6.207.2.6 Variable air volume control for single zone systems. Effective January 1, 2012, all unitary air conditioning equipment and air-handling units with mechanical cooling capacity at ARI conditions greater than or equal to 110,000 Btu/hr that serve single zones shall be designed for variable supply air volume with their supply fans controlled by two-speed motors, variable speed drives or equipment that has been demonstrated to the Executive Director to use no more energy. The supply fan controls shall modulate down to a minimum of [2] / 3 of the full fan speed or lower at low cooling demand.
A6.207.3 Service water-heating systems and equipment.
A6.207.3.1 Certification by manufacturers. Any service water-heating system or equipment may be installed only if the manufacturer has certified that the system or equipment complies with all of the requirements of this subsection for that system or equipment.
§ 25218.5 High relevance — show source text
(b) Certification Requirements for Manufactured Systems, Equipment, Appliances and Building Components.
- Appliances that are within the scope of Section 1601 of the Appliance Efficiency Regulations shall only be installed if they have been certified to the Energy Commission by the manufacturer, pursuant to the provisions of Title 20 California Code of Regulations, Section 1606; or
- Systems, equipment, appliances and building components that are required by Part 6 or the Reference Appendices to be certified to the Energy Commission, which are not appliances that are within the scope of Section 1601 of the Appliance Efficiency Regulations, shall only be installed if they are certified by the manufacturer in a declaration, executed under penalty of perjury under the laws of the State of California, that: A. All the information provided pursuant to the certification is true, complete, accurate and in compliance with all applicable requirements of Part 6; and B. The equipment, product, or device was tested using the test procedure specified in Part 6 if applicable
- The certification status of any system, equipment, appliance or building component shall be confirmed only by reference to: A. A directory published or approved by the Commission; or B. A copy of the application for certification from the manufacturer and the letter of acceptance from the Commission staff; or C. Written confirmation from the publisher of a Commission-approved directory that a device has been certified; or D. A Commission-approved label on the device.
Note: Part 6 does not require a builder, designer, owner, operator, or enforcing agency to test any certified device to determine its compliance with minimum specifications or efficiencies adopted by the Commission.
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5
, 25402.8, and 25943, Public Resources Code.SECTION 110.1—MANDATORY REQUIREMENTS FOR APPLIANCES
(a) Any appliance regulated by the Appliance Efficiency Regulations, Title 20 California Code of Regulations, Section 1601 et seq., may be installed only if the appliance fully complies with Section 1608(a) of those regulations.
(b) Except for those circumstances described in Section 110.1(c), conformance with efficiency levels required to comply with Part 6 mandatory, prescriptive and performance standards shall be verified utilizing data from either:
- The Energy Commission’s database of certified appliances maintained pursuant to Title 20 California Code of Regulations Section 1606, and which is available at: www.energy.ca.gov/appliances/database/ ; or
- An equivalent directory published by a federal agency; or
- An approved trade association directory as defined in Title 20 California Code of Regulations Section 1606(h).
(c) Conformance with efficiency levels required to comply with Part 6 mandatory, prescriptive and performance standards shall be demonstrated either by default to the mandatory efficiency levels specified in Part 6 or by following procedures approved by the Commission pursuant to Section 10-109 of Title 24, Part 1, when:
- Data to verify conformance with efficiency levels required to comply with Part 6 mandatory, prescriptive and performance standards is not available pursuant to subdivision (b); or
- Field verification and diagnostic testing is required for compliance with Part 6 and the Energy Commission has not approved a field verification and diagnostic test protocol that is applicable to the appliance; or
§ 25218.5 High relevance — show source text
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.8, and 25943, Public Resources Code.
SECTION 110.4—MANDATORY REQUIREMENTS FOR POOL AND SPA SYSTEMS AND EQUIPMENT
(a) Certification by manufacturers. Any pool theater for a pool, spa, or a pool and spa combination shall be installed only if the manufacturer has certified that the system or equipment has all of the following:
Efficiency. Equipment subject to State or federal appliance efficiency standards shall comply with the applicable provisions of Section 110.1; and
On-off switch. A readily accessible on-off switch, mounted on the outside of the heater that allows shutting off the heater without adjusting the thermostat setting; and
Instructions. A permanent, easily readable and weatherproof plate or card that provides the energy efficiency rating and instruction for the energy efficient operation of the pool and/or spa heater; and
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ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS
(b) Installation. Any pool and/or spa system or equipment shall meet the following requirements:
- Heating equipment. Equipment installed to heat water for pools and/or spas shall be selected from equipment meeting the standards shown in Table 110.4-A.
TABLE 110.4-A—HEATING EQUIPMENT STANDARDS Col2 HEATING ENERGY SOURCE STANDARD Electric Resistance UL 1261 Gas-fired ANSI Z21.56/CSA 4.7a Heat Pump AHRI 1160 and one of the following: CSA C22.2 No. 236, UL 1995, or UL/CSA 60335-2-40 Solar ICC/APSP 902/SRCC 400 for solar pool heaters, ICC 901/SRCC 100 for solar collectors - Piping. At least 18 inches of horizontal or vertical pipe shall be installed between the filter and the heater or dedicated suction and return lines, or built-in or built-up connections shall be installed to allow for the future addition of solar heating equipment;
- Covers. Outdoor pools and/or spa with electric or gas heating equipment shall be installed with a pool cover.
- Directional inlets and time switches for pools. If the system or equipment is for a pool: i. The pool shall have directional inlets that adequately mix the pool water; and ii. A time switch or similar control mechanism shall be permanently installed as part of a pool water circulation control system that will allow all pumps to be set or programmed to run only during off-peak electric demand period, and for the minimum time necessary to maintain the water in the condition required by applicable public health standards.
(c) Heating source sizing. Heating systems or equipment for pools and/or spas shall meet one of the sizing requirements 1 through 5 below: 1.
§ 150.2 High relevance — show source text
Exception to Section 150.2(b)1Fiii: Entirely new or complete replacement packaged systems for which the manufacturer has verified correct system refrigerant charge prior to shipment from the factory are not required to have refrigerant charge confirmed through field verification and diagnostic testing. The installer of these packaged systems shall certify on the Certificate of Installation that the packaged system was pre-charged at the factory and has not been altered in a way that would affect the charge. Ducted systems shall comply with minimum system airflow rate requirement in Section 150.2(b)1Fiiib, provided that the system is of a type that can be verified using the procedure specified in Section RA3.3 or an approved alternative in Section RA1. G. Altered space-heating system. Altered or replacement space-heating systems shall not use electric resistance as the primary heat source. Exception 1 to Section 150.2(b)1G: Nonducted electric resistance space heating systems, if the existing space heating system is electric resistance. Exception 2 to Section 150.2(b)1G: Ducted electric resistance space heating systems, if the existing space heating system is electric resistance and a ducted space cooling system is not being replaced or installed.
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SINGLE-FAMILY RESIDENTIAL BUILDINGS—ADDITIONS AND ALTERATIONS TO EXISTING RESIDENTIAL BUILDINGS
Exception 3 to Section 150.2(b)1G: Electric resistance space heating systems, if the existing space heating system is electric resistance and the building is located in Climate Zone 7 or 15. H. Water-heating system. Altered or replacement service water-heating systems or components shall meet the applicable requirements below: i. Pipe insulation. For newly installed and existing accessible piping, the insulation requirements of Section 150.0(j)1 shall be met. ii. Distribution system. For recirculation distribution systems: serving individual dwelling units, only demand recirculation systems with manual on/off control as specified in the Reference Appendix RA4.4.9 shall be installed. iii. Water heating system. The water heating system shall meet one of the following: a. A natural gas or propane water-heating system; or b. A single heat pump water heater. The storage tank shall not be located outdoors and be placed on an incompressible, rigid insulated surface with a minimum thermal resistance of R-10. The water heater shall be installed with a communication interface that either meets the requirements of Section 110.12(a) or has an ANSI/CTA-2045-B communication port; or c. A single heat pump water heater that meets the requirements of NEEA Advanced Water Heater Specification Tier 3 or higher; or d. If the existing water heater is an electric resistance water heater, a consumer electric water heater; or e. A water-heating system determined by the Executive Director to use no more energy than the one specified in Item a above; or if no natural gas is connected to the existing water heater location, a water-heating system determined by the executive director to use no more energy than the one specified in Item d above. I. Roofs. Replacements of the exterior surface of existing roofs, including adding a new surface layer on top of the existing exterior surface, shall meet the requirements of Section 110.8 and the applicable requirements of Subsections i and ii where more than 50 percent of the roof is being replaced. i. **Steep-sloped roofs.
§ 18001.8 Medium relevance — show source text
(2) Any manufactured home as defined in Health and Safety Code Section 18007.
(3) Any commercial modular as defined in Health and Safety Code Section 18001.8 or any special purpose commercial modular as defined in Health and Safety Code Section 18012.5.
(4) Any recreational vehicle as defined in Health and Safety Code Section 18010.
(5) Any multifamily manufactured home, as defined in Health and Safety Code Section 18008.7.
For additional information, see Health and Safety Code Sec- tion 18908.
Building Code. The building code that is adopted by this jurisdiction. [HCD 1, HCD 2, OSHPD 1, 1R, 2, 3, 4, 5, 6 & SFM] “Building Code” shall mean the California Build- ing Code, Title 24, Part 2. Building Official. See Authority Having Jurisdiction. For applications listed in Section 1.11.0 regulated by the Office of the State Fire Marshal “Building Official” is the officer charged with the administration and enforcement of this code, or a reg- ular deputy. See “Enforcing Agency.” For the State of Califor- nia, “Building Official” shall be the “Enforcing Agency” as specified in Section 1.11.0.
Burner, Automatic Boiler. A device to convey fuel into the combustion chamber in proximity to its combustion air supply so as to permit a stable, controlled heat release compatible with the burner design and that is equipped with an ignition system to reliably ignite the entire heat release surface of the burner assembly.
205.0 – C –
CAS Number. The Chemical Abstract System registry number.
Central Heating Plant or Heating Plant. Environmental heating equipment installed in a manner to supply heat by means of ducts or pipes to areas other than the room or space in which the equipment is located.
Certified. A formally stated recognition and approval of an acceptable level of competency, acceptable to the Authority Having Jurisdiction. [NFPA 96:3.3.10]
Certified Person. A person trained and certified by the equipment manufacturer, or by a recognized organization through a formal certification program for the system to be serviced or cleaned; that is acceptable to the Authority Having Jurisdiction.
Chilled Water. Water or fluid that is cooled below the surrounding air temperature via mechanical or other means for the purpose of removing excess heat from conditioned spaces or equipment via hydronic piping distribution.
Chimney. One or more passageways, vertical or nearly so, for conveying flue or vent gases to the outdoors. [NFPA 54:3.3.17]
Chimney, Factory-Built. A chimney composed of listed factory-built components assembled in accordance with the manufacturer’s installation instructions to form the completed chimney. [NFPA 54:3.3.17.2] Chimney, Masonry. A field-constructed chimney of solid masonry units, bricks, stones, listed masonry chimney units, or reinforced Portland cement concrete, lined with suitable chimney flue liners. [NFPA 54:3.3.17.3] Chimney, Metal. A field-constructed chimney of metal.
[NFPA 54:3.3.17.4]
Chimney Classifications:
§ 608.3. Medium relevance — show source text
The system shall comply with the expansion tank requirements as described in the California Plumbing Code Section 608.3.
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on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS
- Service water heaters in state buildings. Any newly constructed building constructed by the State shall derive its service water heating from a system that provides at least 60 percent of the energy needed for service water heating from site solar energy or recovered energy, per the statutory requirement of California Public Resources Code Section 25498.
Exception to Section 110.3(c)5: Buildings for which the state architect determines that service water heating from site solar energy or recovered energy is economically or physically infeasible. 6. Isolation valves. Instantaneous water heaters with an input rating greater than 6.8 kBTU/hr (2 kW) shall have isolation valves on both the cold water supply and the hot water pipe leaving the water heater, and hose bibbs or other fittings on each valve for flushing the water heater when the valves are closed. 7. Air-source heat pump water heaters (HPWH). HPWH shall meet the following requirements: A. Backup heat. Backup heat is required for systems where inlet air is unconditioned, unless the compressor cut-off temperature is below the Heating Winter Median of Extremes for the closest location listed in Table 2-3 from Reference Joint Appendix JA2. Backup heat may be internal or external to the HPWH. B. Ventilation. Consumer integrated HPWHs shall meet one of the ventilation requirements below. Minimum volume and opening size requirements shall be the sum of all HPWHs installed within the same space. Compressor capacity shall be determined using AHRI 540 Table 4 reference conditions for refrigeration with the “High” rating test point: i. Installed using a method provided by the manufacturer to meet or exceed the level of performance provided by the ventilation requirements of Section 110.3(c)7B2 through Section 110.3(c)B4. ii. For HPWH installation without ducts, the installation space shall have a volume not less than the greater of 100 cubic feet per kBtu per hour of compressor capacity, or the minimum volume provided by the manufacturer for this method; or
iii. For HPWH installation without ducts, the installation space shall be vented to a communicating space via permanent openings, according to the following requirements: a. Communicating space shall meet the minimum volume of Ssection 110.3(c)7B2 above, minus the volume of the HPWH installation space; and b. Permanent openings shall consist of a single layer of fixed flat slat louvers or grilles, with a total minimum Net Free Area (NFA) the larger of 125 square inches plus 25 square inches per kBtu per hour of compressor capacity, or the minimum provided by the manufacturer for this method. The permanent openings shall be fully louvered doors or two openings of equal area, one in the upper half of the enclosure and one in the bottom half of the enclosure. The top of the upper opening must be 12 inches or less from the enclosure top and the bottom of the lower vent must be 12 inches or less from the enclosure bottom; or iv.
§ 29.3 Medium relevance — show source text
Exceptions:
(1) Water heaters installed in individual dwelling units.
(2) Individual gas water heaters with input capacity not greater than 100 000 Btu/h (29.3 kW). [ASHRAE 90.1:7.5.3] L 503.4.4 Heat Recovery for Service Water Heating. Condenser heat recovery systems shall be installed for heating or preheating of service hot water provided all of the following are true:
(1) The facility operates 24 hours a day.
(2) The total installed heat rejection capacity of the water-cooled systems exceeds 6 000 000 Btu/h (1758 kW) of heat rejection.
(3) The design service water-heating load exceeds 1 000 000 Btu/h (293 kW). [ASHRAE 90.1:6.5.6.2.1]
512 2025 CALIFORNIA PLUMBING CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
APPENDIX L
L 503.4.5 Capacity. The required heat recovery system shall have the capacity to provide the smaller of:
(1) Sixty percent of the peak heat-rejection load at design conditions or
(2) Preheat of the peak service hot-water draw to 85°F (29°C).
Exceptions:
(1) Facilities that employ condenser heat recovery for space heating with a heat recovery design exceeding 30 percent of the peak water-cooled condenser load at design conditions.
(2) Facilities that provide 60 percent of their service water heating from onsite renewable energy or siterecovered energy or from other sources. [ASHRAE 90.1:6.5.6.2.2] L 503.5 Submittals. The Authority Having Jurisdiction shall require submittal of compliance documentation and supplemental information in accordance with Section 104.3.1 of this code.
L 504.0 Solar Water Heating Systems.
L 504.1 General. The erection, installation, alteration, addition to, use or maintenance of solar water heating systems shall be in accordance with this section and the Uniform Solar Energy and Hydronics Code.
L 504.2 Annual Inspection and Maintenance. Solar energy systems that utilize a heat transfer fluid shall annually be inspected unless inspections are required on a more frequent basis by the solar energy system manufacturer.
L 505.0 Hard Water.
L 505.1 Softening and Treatment. Where water has a hardness equal to or exceeding 10 gr/gal (171 mg/L) measured as total calcium carbonate equivalents, the water supply line to water heating equipment and the circuit of boilers shall be softened or treated to prevent accumulation of limescale and consequent reduction in energy efficiency.
L 506.0 Drain Water Heat Exchangers. L 506.1 General. Drain water heat exchangers shall comply with IAPMO PS 92. The heat exchanger shall be accessible.
§ 207.3.2 Medium relevance — show source text
A6.207.3.2 Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section A6.210.1, subject to the following:
- If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
- If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
- Where equipment can serve more than one function, such as both heating and cooling or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
- Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.
A6.207.3.3 Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.
A6.207.3.3.1 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.
A6.207.3.3.2 Temperature controls for public lavatories. The controls shall limit the outlet temperature to 110°F.
A6.207.3.3.3 Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have:
External insulation with an installed R -value of at least R-12; or
Internal and external insulation with a combined R -value of at least R-16; or
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.
A6.207.3.3.4 Service water heaters in state buildings. Any newly constructed building constructed by the State shall derive its service water heating from a system that provides at least 60 percent of the energy needed for service water heating from site solar energy or recovered energy.
Exception: Buildings for which the state architect determines that service water heating from site solar energy or recovered energy is economically or physically infeasible.
A6.207.4 Natural gas central furnaces, cooking equipment and pool and spa heaters: Pilot lights prohibited.
Any natural gas system or equipment listed below may be installed only if it does not have a continuously burning pilot light:
Fan-type central furnaces.
Household cooking appliances. Exception: Household cooking appliances without an electrical supply voltage connection and in which each pilot consumes less than 150 Btu/hr.
Pool heaters.
Spa heaters.
A6.207.5 Controls for space-conditioning systems. Space- conditioning systems shall be installed with controls that comply with the applicable requirements of Subsections A6.207.5.1 through A6.207.5.5.
A6.207.5.1 Thermostatic controls for each zone. The supply of heating and cooling energy to each space-conditioning zone or dwelling unit shall be controlled by an individual thermostatic control that responds to temperature within the zone and that meets the applicable requirements of Section A6.207.5.2.
Frequently asked questions
Who issues the certification the code requires?
The manufacturer issues the certification; for appliances subject to Title 20 the manufacturer must certify to the California Energy Commission (i.e., be listed in the Commission database). For other service water‑heating systems the manufacturer must provide a signed declaration under penalty of perjury and supporting evidence as laid out in § 110.0(b) and § 110.3(a).
What proof should I accept from a manufacturer?
Accept a listing in the Energy Commission’s certified appliance database for Title 20 appliances, or one of the permitted proofs for Part 6 devices: a Commission directory listing, copy of application + acceptance letter, written confirmation from the directory publisher, or a Commission‑approved label; otherwise get the manufacturer’s signed declaration. § 110.0(b)3.
Does the certification replace field testing or commissioning?
No. Part 6 does not require the enforcing agency to perform independent testing of a certified device; but other code sections or local authorities may still require field verification, labeling, or commissioning. The certification is a precondition for installation under § 110.3(a).
If my project uses a heat pump water heater (HPWH), does certification still apply?
Yes. HPWHs must be certified like other service water‑heating equipment, and the installation must meet the HPWH‑specific backup and ventilation/space requirements in § 110.3(c)7.
If I see a manufacturer sticker on the unit, is that enough?
A Commission‑approved label is one acceptable form of evidence, but you should confirm whether the unit is an appliance under Title 20 (requires database listing) or a Part 6 system (requires the manufacturer’s declaration/other acceptable proof). § 110.0(b)3.
More in California Energy Code
- Compliance paths, energy budgets, performance modeling and forms/software requirements
- Controls, commissioning, demand-response, sensors, and field verification/diagnostic testing
- Domestic hot water systems, efficiency, controls and installation requirements
- Electrical infrastructure, EV charging readiness, load management and demand controls
- Envelope construction, insulation, fenestration and thermal performance
- HVAC systems, ventilation rates, ducting, controls and testing
- Interior and exterior lighting power, controls and daylighting requirements
- Mandatory measures, appliance efficiency and certification requirements
- Photovoltaic requirements, BESS (battery energy storage) sizing and SARA procedures
- Reference appendices, test procedures, product certification and labeling requirements
- Scope, applicability, definitions and administrative requirements
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