ADU rules in El Cerrito

Detached ADUs are allowed on any lot zoned for single-family or multifamily residential use (ECMC 19.20.190.C); Table 19.06-A lists ADUs as permitted (P) in the RS districts and L-1 (subject to 19.20.190) in the RD and RM districts. On a single-family lot a detached ADU of up to 800 sq ft with 4 ft side and rear setbacks needs only a building permit (19.20.190.B.1.b; Gov. Code 66323(a)(2)), while a larger one, up to the bedroom-based caps, first goes through a staff-level Planning ADU application. On a lot with an existing multifamily building the city's October 2025 summary allows up to eight detached ADUs (no more than the number of existing units, minimum two), replacing the two that the codified 19.20.190.B.2.b still prints with the Gov. Code 66323(a)(4) count. The commercial and mixed-use use table (19.07.020, Table 19.07-A) still marks ADUs L-1, 'Permitted if an existing use; new uses are prohibited', in the CN, CC and TOM districts, a conflict with 19.20.190.C and Gov. Code 66314 and 66323(a) wherever those districts allow housing.

Attached ADUs (additions that share a wall with the home) and interior ADUs (conversions of space in the home, an attached garage or an accessory structure) are allowed on the same lots as detached units (19.46.030.A.2; 19.20.190.B.1.a and C). One interior ADU plus one JADU goes straight to a building permit; an attached addition needs the Planning ADU application first, must have its entry at least 10 ft behind the main entry or on the side or rear, and if it is on a second story must sit in the rear half of the house (19.20.190.E.4.a, E.5.b). On multifamily lots, non-livable space (storage rooms, garages, attics, basements) can be converted into at least one ADU and up to 25 percent of the existing units (19.20.190.B.2.a; Gov. Code 66323(a)(3)). JADUs of up to 500 sq ft inside a single-family home are limited by 19.20.195.B to the RS districts, narrower than Gov. Code 66323(a)(1), which allows one JADU per lot with a single-family dwelling in any residential or mixed-use zone.

Every ADU is capped at 850 sq ft for a studio or one bedroom and 1,000 sq ft for more than one bedroom (19.20.190.E.2.a); an attached ADU is also held to 50 percent of the existing home or 800 sq ft, whichever is more, and the lower figure applies if that exceeds the bedroom cap (E.2.c). The city's October 2025 summary applies the same numbers, leaves conversions of existing space uncapped, sets JADUs at 500 sq ft, and applies lot coverage (50 percent, or 40 percent on lots sloping more than 30 percent) only to ADUs over 800 sq ft, so an 800 sq ft unit with 4 ft setbacks is always possible (E.7; Gov. Code 66321(b)(3)). Heights per the summary: detached 16 ft, or 18 ft within half a mile of San Pablo Avenue or a BART station (18 ft for detached units on multifamily lots); attached ADUs up to the home's 25 to 35 ft limit if they meet the daylight plane (Figure 19.06-B), otherwise 16 ft. Because the city told HCD in 2025 that it processes ADUs under state law and Gov. Code 66316 voids a noncompliant ordinance, the state defaults (1,200 sq ft detached, attached 50 percent of the existing home under 66314(d)(4)-(5)) are a credible alternative reading; the 850/1,000 figures are what the city's own materials still apply.

No owner occupancy is required for an ADU. The codified 19.20.190.D.5 (Ord. 2021-03) waived owner occupancy only for ADUs permitted from 1-1-2020 through 12-31-2024 and called for an owner-occupancy deed restriction after that, but only 'in accordance with Government Code section 65852.2(a)(6)'; that provision's successor, Gov. Code 66315, bars any owner-occupant requirement with no end date, and the city's ADU page and October 2025 summary list none. For JADUs, 19.20.195.C.4 still requires the owner to live in the home or the JADU, but Gov. Code 66333(b) (as amended by AB 1154, effective 1-1-2026) limits that to a JADU that shares sanitation with the main home and exempts government agencies, land trusts and housing organizations. A JADU still needs a recorded deed restriction barring separate sale and fixing its size and attributes (19.20.195.C.6; 66333(c)).

No off-street parking is required for any ADU or JADU, and a garage, carport or covered parking structure demolished or converted to create one need not be replaced (19.20.190.D.3; 19.20.195.C.1). The ADU row of the parking table in 19.24.040 reads 'No parking spaces are required for ADUs', and the city's October 2025 summary repeats the rule for single-family and multifamily lots. This is more generous than state law, which would let a city require up to one space per unit or bedroom outside the Gov. Code 66322 exemptions (66314(d)(10)).

Approval is ministerial staff review. Interior conversions, JADUs and detached ADUs of up to 800 sq ft go straight to a building permit; detached ADUs over 800 sq ft and attached additions first need an ADU application to the Planning Division with a site plan, floor plan and elevations (city ADU page; the 'Accessory Dwelling Unit Permit' of 19.20.190.B). State law requires a completeness decision within 15 business days, approval or denial within 60 days with no hearing, and an appeal to the Council or Planning Commission (Gov. Code 66317). The codified Administrative Use Permit route (19.20.190.E.6: newspaper notice 21 days ahead, 300-foot mailing, appeal to the Planning Commission) is discretionary but applies only to requests for exceptions to the standards; the Zoning Administrator's architectural-compatibility judgment (D.1) is not an objective standard under Gov. Code 66314(b)(1) and cannot be applied to 66323 units (66323(b)).

Long-term rental is allowed and short-term rental is not. The city's ADU page says ADUs cannot be used for short-term rentals unless the building permit was issued before 1-1-2020 and that rentals must be 31 days or longer, and its Rental Housing page says rentals of less than 30 days are not allowed anywhere in El Cerrito except as bed and breakfasts, which need an Administrative Use Permit and must operate in an owner-occupied single-family dwelling with no separate guest kitchen (19.20.050), so an ADU cannot qualify. The codified text sets a 30-day floor for the building-permit-only ADUs and for JADUs (19.20.190.B; 19.20.195.C.2), while Gov. Code 66323(e) and 66333(g) require terms longer than 30 days for state-exempt units and JADUs, which makes 31 days the working minimum. ADUs cannot be sold or conveyed separately (19.20.190.D.6; Gov. Code 66314(d)(1)) and the code has no Gov. Code 66342 condominium opt-in. A rented ADU needs a business license, a Residential Rental Inspection certificate of compliance (renewed every two years) and annual Rent Registry registration (4.32.260; 16.30.010 to 16.30.040; 10.100.030); there is no local rent control.