ADU rules in Coronado

Coronado allows a detached ADU by right in every zone that permits residential or mixed-use residential development, on a lot with an existing or proposed single-family home or an existing multifamily building (CMC 86.56.105(B)(1)-(2)); Ord. 2026-08 adds lots with a proposed multifamily building. A new detached unit of up to 800 sq ft with 4-ft side and rear setbacks must be approved on any single-family lot (C.2; Gov. Code 66323(a)(2)), and beside an existing multifamily building the codified limit of two detached units (C.4) yields to the eight allowed by 66323(a)(4), never more than the existing unit count, which Ord. 2026-08 writes in. Detached ADUs are one story: the Community Development Director told the Council on 7-21-2026 that two-story ADUs are allowed only as carriage-house conversions above a garage with alley access (86.56.105(D), 86.56.110).

Attached additions and conversions of space inside the home or an accessory structure are allowed by right in the same zones (CMC 86.56.105(B)(2)). One conversion ADU or JADU within existing or proposed single-family space, with up to 150 sq ft added for access, is a mandatory state-exempt type (C.1; Gov. Code 66323(a)(1)), and conversions of non-livable space in existing multifamily buildings are allowed up to 25 percent of the units, at least one (C.3; 66323(a)(3)). Ord. 2026-08 adds ADUs attached to an accessory structure and in attached or detached garages, answering HCD findings 2 and 3. An attached ADU may reach the main home's height limit (B.8.b), and Ord. 2026-08 restates the state rule of 25 ft or the zone limit, whichever is lower (Gov. Code 66321(b)(4)(D)); a JADU of up to 500 sq ft must sit within the walls of a single-family home, attached garages included (66333(d)).

CMC 86.56.105(B)(7) caps an attached or detached ADU at 850 sq ft of floor area for a studio or one bedroom and 1,000 sq ft with more than one bedroom, and (B)(3)(c) requires exceptions to lot coverage, FAR, open space, front setback and size limits so that an 800 sq ft unit with 4-ft side and rear yards can be built; the 800 sq ft detached unit is also a mandatory state-exempt type (C.2; Gov. Code 66323(a)(2)). Conversions of single-family or multifamily space and detached units beside a multifamily building carry no size cap under 66323 (HCD finding 9), which Ord. 2026-08 writes into (B)(7); a JADU is capped at 500 sq ft (B.11.a) and a carriage-house ADU at the carriage house's 400 sq ft second story (86.56.110(F)). Detached ADUs may be 16 ft tall, or 18 ft within one-half mile walking distance of a major transit stop (HCD notes the ferry terminal qualifies) or beside a multistory multifamily building, plus 2 ft for a roof pitch matching the home (B.8; Ord. 2026-08 C.2), while attached units follow the home's height limit. When an ADU is built together with a new home its floor area counts toward the lot's floor area ratio ((B)(4)), as the city applied in 2025 design reviews, whereas the City Attorney told the Council on 7-21-2026 that an ADU proposed after the home has received occupancy is exempt from the FAR calculation.

No owner-occupancy rule applies to ADUs: CMC 86.56.105 contains none and Gov. Code 66315 forbids one. For JADUs the codified text (B.11.c and the B.11.d.iv covenant clause) still requires an owner to live in the home or the JADU in every case, but since 1-1-2026 Gov. Code 66333(b) (AB 1154) permits that condition only where the JADU shares sanitation facilities with the main home and never where the owner is a governmental agency, land trust or housing organization (HCD findings 14 and 16); Ord. 2026-08 writes those exceptions into B.11.c and B.11.d.iv. The codified covenant in 86.56.105(F), recorded for every ADU and JADU, still recites 'owner occupancy requirements'; HCD (finding 30) says no covenant may be imposed on an ADU, and the Ord. 2026-08 redline strikes it, although the ordinance's operative text amends only subsections A, B, C and E.

CMC 86.56.105(B)(12), adopted 'to ensure compliance with the provisions of the California Coastal Act of 1976 and the approved Land Use Plan of the City's Certified Local Coastal Program,' requires at most one space per ADU (none for units deed-restricted to low, very low or extremely low incomes), none for a JADU and one for a converted carriage house, and requires replacement spaces when an ADU or JADU replaces a garage or other required parking (B.12.a-e; E). Gov. Code 66322(a) would otherwise bar parking for units within one-half mile walking distance of public transit, units within the home or an accessory structure, units in a historic district and units filed with a new home, 66323(b) shields state-exempt units from unlisted standards, and 66314(d)(11) bars replacement parking; the city relies on the Coastal Act savings clause in 66329(a) and its finding that the whole city lies in the coastal zone (A.2). HCD (findings 17 to 19 and 28) said the rules may be justified under 66329 but asked the city to cite the specific Coastal Act provisions and weigh less restrictive means; the city defended them and Ord. 2026-08 leaves B.12 unchanged. JADU replacement parking also sits uneasily with 66334(a), which bars additional parking for a JADU.

Applications that meet 86.56.105(B) or (C) are decided ministerially by the Director of Community Development within 60 days of a complete application, without discretionary review or a hearing (86.56.105(E); Gov. Code 66317); Ord. 2026-08 aligns the wording for applications filed with a new home. The whole city lies in the coastal zone and issues coastal permits under its certified LCP chapter 86.70: in the 2021 text, uses permitted without discretionary action are categorically exempt from the city coastal permit outside the Coastal Commission's appeal and direct-permit areas (86.70.060), and 2025-2026 Planning and Design Commission agendas carry coastal permits only with variances or special use permits. Where an ADU does need a coastal permit, the chapter's Planning Commission hearing (86.70.100) yields to Gov. Code 66329(a) (decision within 60 days, no hearing, concurrent with the ADU permit) and the decision is not appealable to the Coastal Commission (66329(c)); HCD finding 31 says 86.70.120, which bars building permits before the coastal permit, must provide for concurrent review.

CMC 86.56.105(B)(10) lets ADUs and JADUs be used only for rentals of six consecutive months or more, and the JADU covenant repeats it (B.11.d.iii). HCD found the six-month term unlawful because Gov. Code 66315 lets a city require only terms of 30 days or longer (findings 11 and 15), and the city's 2025 Housing Element progress report says it applies state law to any project where the zoning code conflicts; Ord. 2026-08 replaces both clauses with 30 days, a term that is one day short for JADUs and 66323 state-exempt units, which must rent for longer than 30 days (66333(g), 66323(e)). Separately, CMC 86.78.060 bars every dwelling or habitable unit in a residential zone from transient rental, meaning occupancy of 25 consecutive days or less (86.78.020-.030), and the city's code enforcement page says rentals must be at least 26 consecutive days. An ADU may not be sold or conveyed apart from the home (B.9); Ord. 2026-08 adds the Gov. Code 66341 qualified-nonprofit exception, and the city has not opted into 66342 ADU condominiums.