ADU rules in Monterey

Detached ADUs are permitted by right on any parcel zoned for single-family or multifamily use: the R-1 and R-3 use tables list Accessory Dwelling Units and Junior Accessory Dwelling Units as P with a pointer to Sec. 38-112.6, which allows a new detached ADU beside an existing or proposed house and up to two detached ADUs beside a multifamily building (Gov. Code 66323(a)(4) now allows up to eight beside an existing multifamily building, never more than its unit count). ADUs and JADUs are barred in Airport Safety Zones 1 and 6 of the 2019 Monterey Airport Land Use Compatibility Plan, and four parcels named by APN must first grant an avigation easement. Every new unit also needs Monterey Peninsula Water Management District water credits: 38-112.6(B)(9) bars ADUs where water or sewer service is inadequate and cites the State Water Board cease and desist order on Cal Am, and the city's March 2026 General Plan report says it cannot approve net new water use until that order lifts, so a project generally relies on credits already on the property (22 ADUs were completed citywide in 2025).

Attached additions, conversions of space inside an existing or proposed house or an existing accessory structure such as a detached garage (with up to 150 sq ft added for entry and exit), and JADUs of up to 500 sq ft inside the walls of a single-family home are all allowed ministerially under Sec. 38-112.6(A)(2) and (D). An attached ADU may be 25 feet tall or the zone's height limit, whichever is lower, and no more than two stories. On a multifamily lot, non-livable space such as storage rooms or garages may be converted into at least one ADU and up to 25 percent of the existing legal units. Locally a single-family lot gets one of three options (a new attached or detached ADU, a conversion, or an ADU plus a JADU when the ADU is a conversion or an 800 sq ft detached unit), but Gov. Code 66323(a) overrides that one-option limit by allowing a converted ADU, a JADU and a detached 800 sq ft ADU in any combination.

Sec. 38-112.6(B)(2)(b) caps the floor area of an attached or detached ADU at 850 sq ft for a studio or one bedroom and 1,000 sq ft for more than one bedroom, and (B)(5) guarantees an 800 sq ft unit with 4-foot side and rear setbacks whatever the lot coverage, floor area ratio, open space or front setback limits. A new detached ADU built together with a JADU is limited to 800 sq ft ((A)(2)(a)(iii)(A), the Gov. Code 66323(a)(2) state-exempt unit), conversions inside existing space are exempt from the local size standard under (A)(5)(a) and 66323(b) (although the city's July 2026 Express Checklist lists the 850/1,000 cap under All ADUs), and JADUs may not exceed 500 sq ft. Heights follow Gov. Code 66321(b)(4): 16 ft detached, 18 ft within one-half mile walking distance of a major transit stop or high-quality transit corridor (plus 2 ft to align with the house's roof pitch) or on a lot with a multistory multifamily building, and 25 ft or the zone limit for attached units; in the R-3 zone a second-story ADU over a detached garage may reach 25 ft only through optional discretionary architectural review, now before the Planning Commission. The caps are worded as floor area while state law sets the 850/1,000 sq ft floors in interior livable space (66321(b)(2)), and HCD's May 11, 2026 letter warns that an outdated ordinance is void under Gov. Code 66316, in which case the state defaults in 66314(d)(4)-(5) (1,200 sq ft detached, 50 percent of the house for attached, never below the 66321(b) floors) would govern.

Sec. 38-112.6 imposes no owner-occupancy rule on ADUs, and Gov. Code 66315 bars one. For JADUs the code ((D)(4)) and the required covenant ((D)(5)(d)) still demand that an owner live in the house or the JADU unless the owner is a government agency, land trust or housing organization, and the city's ADU page and July 22, 2026 checklist repeat that rule. Since January 1, 2026, Gov. Code 66333(b) (AB 1154) allows owner occupancy only where the JADU shares sanitation facilities with the house, and 66339.5 makes the state JADU article supersede conflicting local ordinances, so a JADU with its own bathroom carries no owner-occupancy requirement while a JADU that shares the house's bathroom does.

Sec. 38-112.6(B)(7)(a) requires one additional off-street space per ADU or per bedroom, whichever is less, which may be tandem on an existing driveway or in setback areas, matching the Gov. Code 66314(d)(10)(A) ceiling. No space may be required for an ADU within one-half mile walking distance of a public transit stop, within one block of a car-share pickup, inside an existing or proposed home or an existing accessory structure, in an architecturally and historically significant historic district, or where on-street permits are required but not offered to the ADU occupant ((B)(7)(c), mirroring 66322(a)), and a garage, carport or covered parking demolished or replaced by the ADU need not be replaced ((B)(7)(d); 66314(d)(11) also covers uncovered spaces). State-exempt 66323 units carry no parking because (A)(5)(a) and 66323(b) exempt them from local standards. JADUs need no parking, but (D)(6) still demands replacement of attached-garage spaces a JADU removes, a condition Gov. Code 66334(a) forbids and 66339.5 overrides; whether the transit exemption applies is a site-by-site walking-distance test.

ADUs and JADUs that conform to Sec. 38-112.6(A) are approved ministerially under 38-153(B) through a building permit ((A)(9)), and the city must approve or deny a complete application within 60 days without discretionary review or a hearing ((F)(1)(a); Gov. Code 66317). The only discretionary step is optional architectural review, heard by the Planning Commission since Ord. 3715 C.S. dissolved the Architectural Review Committee effective January 15, 2026, for an applicant who wants an alternative roof pitch or form ((C)(2)) or a second-story ADU over a detached garage above the height limit in the R-3 zone ((B)(4)(c)). In the coastal zone the city has no certified Local Coastal Program, so the city still issues the ministerial ADU permit under 38-112.6 while the California Coastal Commission itself must approve or deny the coastal development permit within 60 days of a complete application, concurrently with the city's review, or the permit is deemed approved (Gov. Code 66329(b), as amended by AB 462 effective October 10, 2025). The local text omits the 15-business-day completeness notice and the appeal process that 66317(a)(2) and (d) now require.

Before a building permit issues, the owner records a covenant that the ADU may not be sold separately from the main dwelling and that neither the ADU nor a JADU may be used for short-term residential rentals of less than 30 consecutive days (38-112.6(A)(3)); the JADU covenant also bars renting for fewer than 30 consecutive days ((D)(5)(c)). Citywide, Chapter 38 defines a short-term residential rental as one of less than a calendar month or 30 consecutive days (38-11), the residential use tables prohibit every unlisted use, Sec. 22-19.5 bans advertising a prohibited short-term rental, and the city's March 2026 General Plan report says any house rental of less than 30 days is illegal in Monterey. A 30-day term is lawful for ordinary ADUs under Gov. Code 66315, but JADUs (66333(g)) and state-exempt units (66323(e)) must rent for longer than 30 days, so the 30-day JADU term yields. Separate sale is allowed only for qualified-nonprofit tenancy-in-common sales under (A)(5)(b) (legacy 65852.26, now Gov. Code 66341), and no record shows a Gov. Code 66342 condominium opt-in. Every rented unit, ADUs included, must be registered each year in the Rental Inventory Program (City Code Chapter 8, Article 2, amended by Ord. 3700 of April 1, 2025), with the $50-per-unit fee waived for owners of three or fewer rental units.