ADU rules in Santee

Detached ADUs are a permitted use (P) in all eight residential districts (HL, R-1, R-1A, R-2, R-7, R-14, R-22, R-30). On a single-family lot one new-construction detached (or attached) ADU of up to 800 sq ft with 4 ft side and rear setbacks needs only a building permit under the state-exempt track (§ 13.10.045(F)(1)(b)), and it can be combined with a converted ADU and a JADU; larger detached units go through the local track in subsection (G). On multifamily lots up to two detached ADUs are allowed, or up to eight beside an existing multifamily building as long as they do not outnumber the existing homes. Detached height is 16 ft, 18 ft within one-half mile of a major transit stop (plus 2 ft to match the main roof pitch) and 18 ft on a lot with a multistory multifamily building, matching the state floors.

Attached ADUs, conversions and JADUs are allowed. Under the state-exempt track one converted ADU (inside the existing or proposed home or an existing accessory structure, plus up to 150 sq ft for entry) and one JADU need only a building permit, and the 800 sq ft new-construction unit in (F)(1)(b) may itself be attached. Larger attached units follow subsection (G) and may reach the zone's height limit (35 ft and two stories in the HL, R-1, R-1A and R-2 districts). JADUs (500 sq ft of interior livable space, inside a single-family home including an attached garage) are limited to lots zoned for single-family homes and need a recorded deed restriction before occupancy.

Section 13.10.045(G)(1) caps local-track ADUs at 850 sq ft of interior livable space for a studio or one-bedroom unit and 1,000 sq ft for two or more bedrooms, and an attached unit added to an existing home is further limited to 50 percent of the home's floor area; lot coverage (25 to 75 percent by zone), front setback and open-space rules can never push a unit below 800 sq ft. The streamlined state-exempt unit is capped at 800 sq ft of total floor area, conversions at the existing space plus 150 sq ft for entry, and JADUs at 500 sq ft. Two warnings: the city's own ADU Guide (Version 2, 'As of July 2026') prints maximums of 800 to 1,200 sq ft for attached and detached units, which the code does not support, and HCD's 5-11-2026 letter says the newest Santee ordinance on file is from 2023, so if Ord. 631 never reached HCD within 60 days it is void under Gov. Code 66326(d) and the state standards (1,200 sq ft detached, 50 percent of the home attached, 800 sq ft always allowed) would apply. Ask the Planning Division which cap it applies before designing a unit over 850 sq ft.

Section 13.10.045(D)(6)(a) states that ADUs are not subject to an owner-occupancy requirement, as Gov. Code 66315 requires. A JADU needs an owner living on the property (in the main home or the JADU) only when it shares sanitation facilities with the main home; a JADU with its own bathroom, or a property wholly owned by a governmental agency, land trust or housing organization, is exempt, which already tracks Gov. Code 66333(b) as amended by AB 1154 and SB 543. The JADU deed restriction covers separate sale and size, not occupancy.

The streamlined units in subsection (F) carry no parking requirement. A local-track ADU under subsection (G) needs one off-street space, which may sit in a setback or be tandem, unless it is within one-half mile walking distance of public transit (any fixed-route bus stop or train station counts), in a historic district, part of the home or an accessory structure, where on-street permits are required but not offered, within one block of a car-share stop, or applied for together with a new home on the same lot. Garages, carports and covered spaces removed for an ADU need not be replaced; the code omits uncovered spaces, but Gov. Code 66314(d)(11) covers them too. Read literally the one-space rule also reaches a studio, while Gov. Code 66314(d)(10)(A) caps parking at one space per unit or per bedroom, whichever is less; the city guide describes parking as required only for units over 800 sq ft more than one-half mile from transit.

ADU and JADU applications are approved ministerially with only a building permit, without discretionary review or a hearing, under both the streamlined track (F) and the local track (G). The city must decide completeness within 15 business days and approve or deny a complete application within 60 days or it is deemed approved, and an applicant may appeal an incompleteness finding or a denial in writing to the City Council, which must answer within 60 business days. Sites inside the Gillespie Field Airport Influence Area get an aviation compatibility check that can add sound attenuation or an overflight notification, but the airport plan treats ADUs on individual lots as compatible.

Section 13.10.045(D)(3) bars renting any ADU or JADU for a term shorter than 30 days regardless of when it was built, which is lawful for ordinary ADUs under Gov. Code 66315; for JADUs (66333(g)) and units approved on the state-exempt track (66323(e)) state law requires terms longer than 30 days, so those need at least 31 days. ADUs may be rented but not sold or conveyed separately from the lot except as Gov. Code 66341 allows (qualified nonprofits); Santee has not opted into the 66342 ADU-condominium regime. The Municipal Code has no short-term rental permit chapter (the phrase appears only in the SB 9 sections), and the city's 2026 ADU Guide states that short-term rentals are not allowed in the city.