A Code Coach inquiry came in last month that had us digging through CALGreen, the Plumbing Code, State Law and eventually a direct inquiry to California Housing & Community Development (HCD). The question is: are ADU’s subject to the CAL Green requirement for residential water submeters for multifamily buildings? The short answer is, yes!
CALGreen Section 4.303.2 reads: “Submeters for multifamily buildings and dwelling units in mixed-use residential / commercial buildings. Submeters shall be installed to measure water usage of individual rental dwelling units in accordance with the California Plumbing Code.”
According to the CALGreen Guide, this code section is meant to comply with SB 7 (Chapter 623/Statute of 2016) which specifically notes that the submeter requirement is applicable to “…real property containing two or more dwelling units that is served by a single master meter.” In other words, if you have more than one household served by a single water meter, you need a submeter to accurately track water use for each unit. It may or may not be tied to dividing up a water bill, but either way it tracks actual consumption, which provides transparency and incentivizes water conservation.
By the energy code, the addition of a new Accessory Dwelling Unit, or ADU, does not define the property as “multifamily”, so the CALGreen section referenced above may not appear applicable. In addition, by State law, ADU’s are sometimes exempt from other code requirements such as parking, so the ADU question adds another layer of inquiry.
So, we assembled the background information and posed the question to HCD: Are ADU’s and/or JADU’s exempt from CALGreen requirements for water sub-meters? Here is their response:
Thanks for your question. While State ADU Law does provide some protections for ADUs regarding imposition of connection fees and capacity charges under Government Code Section 66324, subdivisions (b) and (d), metering is, of course, not the same as providing a new connection. As a result, I would agree that ADUs are likely not exempt from the sub-metering requirement you mention, as there is nothing in state ADU law that specifically provides an exemption to this requirement.
If an ADU is part of a “real property containing two or more dwelling units that is served by a single master meter” per the Guide, then the ADU would have to meet this sub-metering requirement.
Fortunately, the requirement itself is not onerous. A submeter is defined as “a secondary device beyond a meter that measures water consumption of an individual rental unit within a multiunit residential structure or mixed-use residential and commercial structure”. It can be installed for a few hundred dollars and higher end models are available that can be read remotely on a smart phone.
One additional nuance: If the main house and ADU share a hot water heater, as allowed under the Energy Code, the property owner may need to add a second submeter for the hot water, again for transparency and accounting.
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