Multifamily Water Heater Replacement Title 24 Requirements
Replacing a water heater that serves one apartment is an alteration under Section 180.2(b)3. A natural gas or propane unit is on the list, a single heat pump water heater is allowed with conditions, and a consumer electric tank is allowed only where the existing heater is electric resistance. Central plant replacements are assessed differently.
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The replacement menu for one dwelling unit
- A natural gas or propane water heater. Gas stays available in an existing building, even though new low-rise construction cannot use individual gas instantaneous units.
- A single heat pump water heater with the tank not outdoors, on a rigid insulated base of R-10 or better, and a communication interface that meets Section 110.12(a) or an ANSI/CTA-2045-B port.
- A single heat pump water heater that meets NEEA Advanced Water Heater Specification Tier 3 or higher.
- A consumer electric water heater, only where the existing heater is electric resistance.
What comes with the heater
Pipe insulation under Section 160.4(e) goes on new piping and on accessible existing piping. Recirculation serving the one unit must be demand recirculation with manual on and off control. Section 180.2(b) does not list Section 160.9 among the sections an altered component must meet, so a gas swap does not by itself bring the electric-ready wiring package. A heat pump unit under Section 110.3(c)7 needs backup heat when it draws unconditioned air, unless its compressor cut-off sits below the winter median of extremes, plus either 100 cubic feet of space per kBtu/h of compressor capacity or permanent vent openings.
Central plants are a different question
That list is written for equipment serving individual dwelling units. For a boiler or tank serving several units, Exceptions 1 and 2 to Section 180.2 leave existing systems alone when they are expanded or moved, and the manual's performance commentary uses the existing efficiency level as the standard design. Confirm the path with the building department before ordering equipment.
Paperwork
Section 180.2(b)3 lists no field verification for these options, so Section 10-103(a)1C lets the department waive the certificates or accept a simplified form. The permit itself is still the department's call; see water heater permits. Central new-construction rules, such as recirculation and mixing valves, are on multifamily water heating; heat pump installation details are on heat pump water heater installation. Unit-wide work is covered on apartment unit remodels, and reports at the multi-family service.
Common Title 24 Questions
- Do apartments need Title 24?
- Does a duplex need Title 24?
- Do triplexes and fourplexes need Title 24?
- Which Title 24 forms does a multi-family project use?
- What is an LMCC certificate?
- How much does a multi-family Title 24 report cost?
Frequently Asked Questions
Not under the prescriptive list. A consumer electric water heater is allowed only where the existing heater is electric resistance; otherwise choose gas, a single heat pump water heater, or the performance route.
Section 180.2(b) does not list the electric-ready Section 160.9 among its requirements, so the wiring package is a new-construction item unless the building department says otherwise.
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View all Multi-Family guides → · Permits and Compliance · Title 24 guide