Town Permit Guide

Home › California › San Clemente › Accessory Dwelling Units (ADUs)

Can I build an ADU in San Clemente, California?

San Clemente, Orange County · Ordinances checked 2026-10-05 · Reviewed · 9 cited sections

Allowed with a permit

Yes. San Clemente approves ADUs and junior ADUs in any residential zone with just a building permit. On a single-family lot you can have one attached ADU, one new detached ADU (up to 850 sq ft, or 1,000 sq ft with two or more bedrooms, and 16 ft tall), one converted detached structure, and one junior ADU of up to 500 sq ft.

Approval neededBuilding permit only, in any residential or mixed-use zone [1]
Detached new ADU per single-family lot1 (plus 1 converted detached structure and 1 JADU) [2]
Max ADU size850 sq ft (studio/1-bed); 1,000 sq ft (2+ bedrooms) [3]
Max JADU size500 sq ft [4]
Max detached ADU height16 ft (18 ft near major transit) [5]
Side and rear setback4 ft (none for conversions) [6]
Parking1 space per ADU, with many exemptions [7]
Minimum rental termMore than 30 days [8]
Owner-occupancyOnly for a JADU that shares a bathroom with the house [9]

Where and how they're approved

San Clemente's ADU rules are in Municipal Code §17.28.270. ADUs and junior ADUs (JADUs) are approved in any residential or mixed-use zone, subject only to a building permit, as long as there's an existing or proposed home on the lot [1]. There's no minimum lot size.

How many on a single-family lot

You can combine one attached ADU (built within or added to the house), one new detached ADU [2], one converted detached accessory structure, and one JADU inside the house.

Size and height

  • ADUs: up to 850 sq ft for a studio or one bedroom, or 1,000 sq ft for two or more bedrooms [3]. Conversions of existing space aren't capped. Setbacks, floor area and coverage rules can't shrink an ADU below 800 sq ft.
  • JADUs: up to 500 sq ft [4], with their own exterior entrance.
  • Detached ADUs: 16 ft tall, or 18 ft within half a mile of a major transit stop (plus 2 ft to match the house's roof pitch) [5]. Attached ADUs follow the zone's height limit.

Setbacks

New attached and detached ADUs need 4 ft from side and rear lot lines [6]. Converting or rebuilding an existing garage or structure in the same footprint needs no added setback. The zone's front setback applies unless it would block a qualifying ADU.

Parking and fees

One parking space is required per ADU [7], tandem or on the driveway. None is needed for a JADU, a conversion, an ADU within half a mile of public transit, or a few other cases. In the coastal zone, two of these exemptions don't apply: the one for building an ADU together with a new house, and the one that waives replacement parking when a garage, carport or covered parking is demolished for or converted to an ADU. So in the coastal zone, converting a garage may mean providing replacement parking. ADUs under 750 sq ft pay no impact or connection fees.

Rentals and ownership

ADUs can be rented but not sold separately. They can't be rented for 30 days or less [8]. A JADU that shares a bathroom with the house requires the owner to live on the property [9], and a JADU needs a recorded deed restriction.

State law

State ADU law applies on top of these rules. State law bars cities from requiring replacement parking when a garage is converted to an ADU, but it also says the ADU law doesn't lessen the Coastal Act, so it's unsettled whether the city's coastal-zone parking rules hold; state law may override them. Starting January 1, 2027, state law (AB 956) will require cities to approve two new detached ADUs on a single-family lot; San Clemente's code currently allows one new detached ADU plus one converted detached structure.

See how San Clemente compares with 8+ other California towns on accessory dwelling units (adus) →

Next steps

  1. Check your lot's zone and whether it's in the coastal zone with the San Clemente Planning Division.
  2. Prepare building plans showing the ADU's size, height, 4 ft side and rear setbacks, and any required parking space.
  3. Apply for a building permit with Building Services (949-361-6100).
  4. For a JADU, record the City's deed restriction with the County Recorder and file a copy with the Planning Division before the permit is issued.

Common questions

Can I build an ADU in San Clemente, California?
Yes. San Clemente approves ADUs and junior ADUs in any residential or mixed-use zone with just a building permit, as long as there's an existing or proposed home on the lot. There's no minimum lot size.
How big can an ADU be in San Clemente, California?
A new ADU can be up to 850 sq ft for a studio or one bedroom, or 1,000 sq ft for two or more bedrooms. A junior ADU can be up to 500 sq ft. Conversions of existing space aren't capped, and a detached ADU can be 16 ft tall, or 18 ft near major transit.
How many ADUs can I have on a single-family lot in San Clemente, California?
You can combine one attached ADU, one new detached ADU, one converted detached accessory structure and one junior ADU inside the house. Starting January 1, 2027, state law (AB 956) will require cities to approve two new detached ADUs on a single-family lot.
What are the ADU setback and parking requirements in San Clemente, California?
New attached and detached ADUs need 4 ft from side and rear lot lines; conversions in the same footprint need no added setback. One parking space is required per ADU, with exemptions such as JADUs, conversions and ADUs near transit, though in the coastal zone converting a garage may mean providing replacement parking.
Can I rent my ADU on Airbnb in San Clemente, California?
No. ADUs can be rented but not for 30 days or less, and they can't be sold separately. A JADU that shares a bathroom with the house requires the owner to live on the property.

California's statewide ADU law

California's ADU law (Gov. Code §§66310–66342, recodified from §65852.2; latest amendments effective January 1, 2026) overrides conflicting city rules, including in charter cities. Cities must approve ADUs ministerially (no hearing) within 60 days of a complete application, or the permit is deemed approved.

What cities cannot require or do:

  • Owner-occupancy for an ADU.
  • A minimum lot size.
  • Side or rear setbacks over 4 feet for a new ADU, or any setback for a converted existing structure.
  • Size, lot coverage or floor-area rules that block an ADU of at least 800 sq ft. Size caps can't be under 850 sq ft (1,000 for 2+ bedrooms).
  • Parking within half a mile walking distance of public transit, or replacement parking for a garage converted to an ADU.
  • Impact fees on ADUs of 750 sq ft or less.

By right on a single-family lot: one converted ADU plus one junior ADU (JADU, up to 500 sq ft inside the house), plus one new detached ADU (up to 800 sq ft, 16 ft tall). Owner-occupancy may be required only for a JADU that shares a bathroom.

Short-term rentals: cities may bar ADU rentals under 30 days, and must for by-right ADUs, JADUs and SB 9 units.

Coming January 1, 2027: AB 956 raises the by-right count to two new detached ADUs per single-family lot.

SB 9 (§§65852.21, 66411.7) allows two homes on a single-family lot, or a split into two lots of at least 1,200 sq ft (with a 3-year owner-occupancy affidavit).

State sources: Gov. Code §66314 (ADU ordinance standards) · Gov. Code §66315 (no owner-occupancy requirement) · Gov. Code §66317 (ministerial review, 60-day deadline) · Gov. Code §66321 (size, setback and height limits on local rules) · Gov. Code §66322 (parking exemptions) · Gov. Code §66323 (by-right ADUs and JADUs) · Gov. Code §66333 (junior ADUs) · Gov. Code §66311.5 (impact fees) · AB 956 (2026), Stats. 2026, ch. 791 · Gov. Code §65852.21 (SB 9 two-unit projects) · Gov. Code §66411.7 (SB 9 urban lot splits) · HCD, Accessory Dwelling Units (ADU Handbook, updated March 2026)

What the ordinance says

Exact text from San Clemente's published ordinances. Section numbers are as printed in the source.

  1. §17.28.270(C) Review Authority, Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    Accessory dwelling units and junior accessory dwelling units shall be approved in any residential or mixed-use zoning district, and within commercial zoning districts where residential development is authorized pursuant to the Housing Overlay or applicable State law, subject to issuance of a building permit and the following conditions:
  2. §17.28.270(D)(2), Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    One detached new-construction ADU may be permitted on a lot with a proposed or existing single-family dwelling.
  3. §17.28.270(E)(4)(a), Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    The maximum size of a detached or attached accessory dwelling unit shall be 850 square feet of interior livable space for a studio or one bedroom unit and 1,000 square feet of interior livable space for a two or more bedroom unit.
  4. §17.28.270(E)(4)(d), Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    The maximum size of a junior accessory dwelling unit shall be 500 square feet of interior livable space.
  5. §17.28.270(E)(3)(c), Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    Detached accessory dwelling units shall not exceed a height of 16 feet except as noted below:
  6. §17.28.270(E)(2)(c), Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    Attached and detached accessory dwelling units shall provide a minimum setback of four feet from all side property lines and rear property lines not abutting an alley unless the setback requirements of the underlying zoning district are less restrictive.
  7. §17.28.270(E)(9)(a), Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    One parking space shall be required for each accessory dwelling unit.
  8. §17.28.270(G)(2) Short-Term Lodging, Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    The accessory dwelling unit and/or junior accessory dwelling unit shall not be rented for periods of 30 days or less.
  9. §17.28.270(G)(3), Municipal Code Title 17 Ch. 17.28 Special Uses (17.28.060 animals, large species; 17.28.160 home occupations; 17.28.270 accessory dwelling units; 17.28.292 short term lodging units)
    If the JADU has its own bathroom, then the property owner is not required to reside on the property.
This page summarizes San Clemente's posted ordinances as of 2026-10-05. Ordinances are amended, and individual lots can have overlays, subdivision covenants, or HOA rules that are stricter. Confirm with City of San Clemente Code Compliance Division (Community Development), 910 Calle Negocio; Building Services 949-361-6100 (949-366-4705) before you build. Spot an error?