ADU Update: What Avenues does the State ADU Law Provide?

California’s ADU law

California’s Accessory Dwelling Unit (ADU) law underwent significant changes in 2020. The new law is very prescriptive, it allows property owners to bypass a wide range of local planning and zoning rules to construct ADUs and Junior accessory dwelling units (JADUs). JADUs are smaller ADUs, not more than 500 sq. ft. in size.

The ADU law is found in Ca Gov Code § 65852.2, the new and highly prescriptive portion is subdivision (e). However, the law in only prescriptive in certain situations, if certain prerequisites are met. The main prerequisite for subdivision (e) is that the property is zoned residential or mixed use. But if the zoning is any sort of residential or mixed use, the specific zoning rules are then basically ignored, and Subdivision (e) basically force the city or local planning authority to approve ADU’s in four situations. Which of these situations can apply is largely determined by what structures currently exist on the property, not by local planning or zoning rules. 

These rules also sometimes apply to ‘planned structures’ which have planning permissions but are not yet built. But because most ADU projects involve preexisting structures, I will not really be getting into that.

Option A: Converting space in Single family dwelling                                                      CA Gov § 65852.2 (e)(1)(A)

Option A Prerequisites: 

o   Zoned residential or mixed use

o   Proposed or existing Single-family dwelling

o   New ADU/JADU has extended access from the existing single-family dwelling

o   Side and rear setbacks sufficient for fire safety

o   Must comply with JADU rules in CA Gov § 65852.22 if proposed unit is less than 500 sq. ft. in size

Option A Allows:

o   One ADU or JADU within the existing space of the home or accessory structure (such as a garage)

o   May include expansion of 150 sq. ft. beyond the physical dimensions of the existing accessory structure, but only for accommodating ingress and egress

Option B: Detached ADU on a Single Family lot                                                                  CA Gov § 65852.2 (e)(1)(B)

Option B Prerequisites: 

o   Property is zoned residential or mixed use

o   Proposed or existing Single-family dwelling

Option B Allows:

o   One new construction ADU, detached from main dwelling with 4 ft. side and rear yard setbacks

o   Can be combined with Option A

o   Cities can, and usually do, limit these ADUs to 800 sq. ft with a 16 ft. height limit

Option C: Converting non-housing spaces in Multiunit housing              CA Gov § 65852.2 (e)(1)(C)

Option C Prerequisites: 

o   Property is zoned residential or mixed use

o   There are existing non-living spaces in multiunit dwelling, such as storage rooms, boiler rooms, attics, basements, or garages

Option C Allows:

o   A number of new ADUs equal to 25% of existing housing units, or one ADU at the minimum

o   These ADUs must comply with state building standards,

o   If ADUs are built where parking was located, that parking usually does not need to be replaced elsewhere.

Option D: Detached ADUs on a multifamily lot                                      CA Gov § 65852.2 (e)(1)(D)

Option D Prerequisites: 

o   Property zoned residential or mixed use

o   Existing multifamily dwelling

o   ADUs must be detached from multifamily dwelling

Option D Allows:

o   One or two detached ADUs, subject to height limit of 16 ft. and 4 ft. rear and side yard setbacks.

If your property fits the prerequisites for one of these options, the next step is checking the rules for the city the property is located in. These rules generally cannot impose any major conditions beyond what the state law sets. But in rare situations local cities have ADU rules less stringent than the state baseline, such as allowing a 25 ft. height limit for detached ADUs rather than 16 ft.

            I want to reiterate the main point here: the ADU law is very prescriptive, but only in specific situations. As a result, cities often will permit what the letter of the law provides, but deny more elegant solutions for ADU’s which preserve parking or are lower impact for current residents but do not fit exactly with the state law.

            As for parking, there is a very prescriptive set of parking rules for ADUs located in CA Gov §65852.2(d). Local agencies and cities cannot require parking spots for ADU or JADUs in most situations. Garage conversions are exempt from parking requirements. ADUs built within one-half mile walking distance of public transit (such as a bus stop) are exempt. ADUs and JADUs built within prexisting dwelling structures are also exempt from parking requirements. Furthermore, if parking spaces are demolished or converted to build an ADU, those spaces need not be replaced under CA Gov §65852.2(a)(1)(D)(xi).

            Although the new ADU rules do not work for every situation, they do allow several ways for property owners to cut through local rules and create ADUs which provide a financial benefit to their owners as well as some of the new housing our state desperately needs.