ADU rules in South Gate

South Gate allows a detached ADU on any lot with a proposed or existing primary dwelling in a zone where residential use is permitted or conditionally permitted (SGMC 11.43.030(A), restated by Ord. No. 2025-01-CC, adopted 10-14-2025). On single-family lots the code lists a detached new-construction unit of up to 800 sq ft with 4-ft side and rear setbacks (11.43.030(B)(1)(b)); a larger detached unit follows the 850/1,000 sq ft caps, 4-ft side and rear setbacks, 6-ft building separation and 16-ft height in 11.43.050. Lots with an existing multifamily building may add up to eight detached ADUs (never more than the existing unit count), and lots with a proposed multifamily building two (11.43.030(B)(2)(b)). The 2018 use table that still shows 'Second Dwelling Unit' as permitted only in the NL zone yields to 11.43.030(A) and Gov. Code 66314 and 66323.

Conversions inside the existing or proposed home or an accessory structure (with up to 150 sq ft added for access) are allowed together with a JADU (11.43.030(B)(1)(a)), and an ADU attached to an existing home is capped at the smaller of 850/1,000 sq ft or 50 percent of the home (11.43.050(A)(2)). In existing multifamily buildings at least one ADU and up to 25 percent of the unit count may be created from non-livable space such as storage rooms, attics, basements or garages (11.43.030(B)(2)(a)). The local count rule offers the conversion ADU and the detached 800 sq ft unit as alternatives, but HCD's 3-16-2026 findings (item 3) say SB 543 lets them combine and that one more ADU under Gov. Code 66314 (detached, attached or conversion) may be added. Attached units may not change street-facing walls or existing floor and roof elevations (11.43.050(L)(1)), a design rule HCD says cannot reach state-exempt 66323 units.

SGMC 11.43.050(A)(1) caps an ADU's total floor area at 850 sq ft with one bedroom or less and 1,000 sq ft with more than one bedroom, and (A)(2) limits an ADU attached to an existing home to the smaller of that figure or 50 percent of the home's floor area; Gov. Code 66321(b)(3) still guarantees at least 800 sq ft of interior livable space with 4-ft side and rear setbacks. The detached new-construction unit on a single-family lot is capped at 800 sq ft (11.43.030(B)(1)(b)), accessory structures on single-family lots may be converted and expanded to 1,000 sq ft (11.43.050(G)(1)), and JADUs at 500 sq ft. Heights are 16 ft detached, 18 ft within half a mile of a major transit stop or high-quality transit corridor (plus 2 ft for a roof pitch matching the house) or beside a multistory multifamily building, and for attached units 25 ft or the zone limit if lower, never more than two stories (11.43.050(E)). HCD's findings (items 2 and 7) say the caps must be measured in interior livable space and cannot apply to conversions or to detached units on multifamily lots under 66323(a)(4), which carry no state size cap.

SGMC 11.43.040(G)(1) says no owner must live in either the main home or the ADU, matching Gov. Code 66315. The codified 11.43.040(G)(2) still requires owner occupancy for every JADU, but Gov. Code 66333(b) as amended by AB 1154 (effective 1-1-2026) allows that requirement only when the JADU shares sanitation facilities with the main home; HCD's finding 5 flags the clause and the pending 2026 amendment narrows it accordingly. A JADU still needs a recorded deed restriction barring separate sale and fixing its size (11.43.040(F)), and an ADU sold separately to a qualified buyer under 11.43.040(H) must be the buyer's principal residence.

Ord. No. 2025-01-CC reversed the 2021 no-parking rule: SGMC 11.43.050(H) now requires one off-street space per ADU, which may be tandem on a driveway or in setback areas. The six state exemptions are copied in: within one-half mile walking distance of public transit (11.43.020(V) counts any fixed-route bus stop), in a historic district, part of the proposed or existing home or an accessory structure, where on-street permits are required but not offered, within one block of a car share vehicle, or applied for together with a new single-family or multifamily dwelling; JADUs need none and garage spaces lost to an ADU need not be replaced. In a preferential parking district only the primary dwelling and the first permitted ADU get residential permits (8.12.090(E)(2)(a)), so a second ADU there qualifies for the permit exemption. On a plain reading the flat one-space rule exceeds Gov. Code 66314(d)(10)(A) (one space per unit or per bedroom, whichever is less) for studios and cannot reach state-exempt 66323 units (66323(b)), although HCD's March 2026 letter did not raise parking.

SGMC 11.43.060(A) requires a complete application to be approved or denied within 60 days and considered and approved ministerially, without discretionary review or hearing; the Community Development Director issues the ADU permit (11.43.020(B)) and may attach only conditions consistent with the chapter (11.43.060(C)), and a denial must list the deficiencies and how to cure them (11.43.060(D)). In practice plans go to Planning plan check by email (about two weeks), then Building and Safety plan check and a building permit, and the city offers pre-approved garage-conversion standard plans and a permit-ready new ADU plan for single-family parcels. Gov. Code 66317 adds the 15-business-day completeness notice and an appeal path; HCD's finding 12 notes the local delay rule covers only a new single-family home, not a new multifamily building.

SGMC 11.43.040(C) lets an ADU be rented separately from the main home for terms of not less than thirty days and bars selling or conveying it separately except under 11.43.040(H), the qualified-buyer and qualified-nonprofit path that mirrors Gov. Code 66341; South Gate has not opted into 66342 ADU condominiums. The 30-day floor is lawful for ordinary ADUs under 66315, but 66323(e) and 66333(g) require terms longer than 30 days for state-exempt units and JADUs, so the local text is one day short for those. The code has no short-term rental chapter, the residential zone use table lists no lodging use and 11.21.020(B) bars unlisted uses, and code searches found no rent stabilization, just-cause or rental registry ordinance.