ADU rules in Carlsbad

Detached ADUs are allowed in every zone that allows one-family, two-family, multiple-family or mixed-use dwellings when a home exists or is proposed (CMC 21.10.030.D.1): they are an accessory use in the R-A, R-E, R-1, R-2, R-3, R-P, R-T, R-W and RD-M tables and the C-2 and C-L tables, in the P-C zone through 21.38.025, and in the Village and Barrio Master Plan districts. Approval is ministerial, by building permit outside the coastal zone and with an added Minor Coastal Development Permit inside it (21.10.030.B). On a single-family lot the city allows one local-track attached or detached ADU (detached up to 1,200 sq ft) plus one conversion ADU and one JADU, or the state-exempt detached unit of up to 800 sq ft with 4-ft side and rear setbacks (Gov. Code 66323(a)(2)). Outside the coastal zone Ord. CS-506 defers multifamily counts to 66323(a)(4) (up to eight detached ADUs beside an existing multifamily building, never more than its units, two with a proposed one); inside the coastal zone the city still applies the certified 2023 text and allows two (IB-111).

Attached ADUs (new additions sharing a wall with the home) and conversion ADUs inside the existing or proposed home or an accessory structure are allowed on the same terms as detached units (CMC 21.10.030.D.1, E.3.a-b), and one JADU of up to 500 sq ft is allowed within a single-family home or its attached garage in zones that allow one-family dwellings (D.2, E.3.d). A conversion may add up to 150 sq ft for ingress and egress (IB-111; Gov. Code 66323(a)(1)). On two-family and multifamily lots ADUs may be converted from non-livable space (storage rooms, basements, garages) up to 25 percent of the existing units, at least one (66323(a)(3)); JADUs are not allowed there. Inside the coastal zone attached ADUs and JADUs are exempt from a coastal development permit unless a 21.201.060(B)(1) exception applies.

Ord. CS-506 caps a detached ADU on a one-family lot at 1,200 sq ft and an attached ADU that adds new floor area at 50 percent of the main dwelling or 1,200 sq ft, whichever is less, but never below 800 sq ft; a conversion must stay inside the existing or proposed home or accessory structure, a JADU stops at 500 sq ft, and detached ADUs on two-family and multifamily lots follow Gov. Code 66323 with no stated cap (21.10.030.E.3). The state-exempt detached unit is 800 sq ft of livable space with 4-ft side and rear setbacks, which may intrude into the front setback when nothing else fits (IB-111). Heights: detached 16 ft, 18 ft within one-half mile walking distance of a major transit stop (Carlsbad Village or Poinsettia station) or a high-quality transit corridor with 2 more feet to match the main roof pitch (20 ft maximum), 18 ft on a lot with a multistory two-family or multifamily building; attached 25 ft or the zone height, whichever is higher, up to two stories; an ADU above or below a detached garage keeps to the zone height and one story (E.4). Detached ADUs over 800 sq ft, and attached ADUs over 800 sq ft and taller than 16 ft, count against the zone's lot coverage limit (IB-111). Inside the coastal zone the certified 2023 text carries the same size caps and pairs the 16-ft detached limit with a one-story limit.

Carlsbad imposes no owner-occupancy requirement on ADUs: IB-111 (Aug. 2026) states 'ADUs are exempt from owner-occupancy requirements,' as Gov. Code 66315 requires, and Ord. CS-474 (2024) deleted the clause that let the city keep enforcing owner occupancy on ADUs permitted before 2020. For a JADU the owner must live in the main home or the JADU only when the JADU shares sanitation facilities with the home (IB-111; Gov. Code 66333(b) as amended by AB 1154). Ord. CS-506 removed the code's own JADU owner-occupancy language outside the coastal zone, and its JADU deed restriction now covers only the ban on separate sale and the unit's size and attributes (21.10.030.E.11). The certified coastal-zone text still says the owner must reside in the primary residence or the JADU for every JADU, a clause that yields to 66333(b).

An ADU needs one off-street space, covered or uncovered and allowed as tandem parking on a driveway or in the front or side setback, on top of the primary home's parking (CMC 21.44.020 Table A; 21.44.060 Table C), unless a Gov. Code 66314 or 66322 exemption applies (21.10.030.E.9.a): within one-half mile walking distance of public transit (IB-111 counts the Carlsbad Village and Poinsettia stations and bus stops), in a historic district, part of the existing or proposed home or an accessory structure, where on-street permits are required but not offered, within one block of a car share vehicle, or filed with an application for a new home on the lot. JADUs need none (E.9.b; 66334), and the state-exempt 66323 units carry no parking under 66323(b). A garage, carport, covered or uncovered space demolished or converted for an ADU need not be replaced, except on lots west of the rail corridor and between the rail corridor and I-5 from Avenida Encinas to Batiquitos Lagoon (the mapped ADU Parking Replacement Areas), where lost spaces must be replaced as covered, uncovered, tandem or lift spaces (E.9.c). Inside the coastal zone the certified text exempts only garages, carports and covered structures, so uncovered spaces must also be replaced there (IB-111).

ADU and JADU applications are ministerial, with no discretionary review or public hearing when 21.10.030 is met (B.1), and the city acts within the Gov. Code 66317 clock (completeness in 15 business days, a decision within 60 days, per IB-111). Outside the coastal zone a building permit is the only approval (B.2). Inside the coastal zone a detached ADU also needs a Minor Coastal Development Permit (Form P-6) that the City Planner decides after a 10-day neighbor notice, with no administrative hearing and no appeal to the Planning Commission or City Council (21.201.080.B.1, C.1.a.ii; 21.201.120.A); attached ADUs and JADUs need no coastal permit unless a 21.201.060(B)(1) exception applies (beach or bluff-edge sites, 10 percent expansions near the beach, or a home nonconforming with habitat buffers or geologic setbacks). Gov. Code 66329 bars hearings on ADU coastal permits, sets the same 60-day clock and, since AB 462 (10-10-2025), removes Coastal Commission appeals of the local decision.

ADUs and JADUs may be rented long term, but CMC 5.60.020 (Ord. CS-383, 2020) excludes every ADU and JADU issued a building permit on or after 1-1-2020 from the short-term vacation rental definition, and the city's STVR page applies that as a bar ('prohibited from being an STVR'). STVRs of any dwelling are allowed only in the coastal zone and the La Costa Resort and Spa Master Plan area (5.60.030), with an annual STVR permit (new $231 fee for applications after 9-1-2026), a business license and transient occupancy tax, so only a pre-2020 ADU in those areas can be rented by the night. IB-111 says ADUs must be rented for at least 30 days and JADUs at least 31 days, matching Gov. Code 66315 (terms of 30 days or longer) and 66333(g) and 66323(e) (longer than 30 days for JADUs and state-exempt units). Inside the coastal zone the certified LCP text still requires a recorded notice of restriction barring rentals under 30 days for units permitted since 2020. An ADU may be sold separately only under the 66341 nonprofit path; the city has not opted into 66342 condominium sales (IB-111; 21.10.030.E.12).