ADU Builder in Santa Monica, CA: Permits, Costs and Local Rules

What does the Santa Monica ADU ordinance cover?

Santa Monica Municipal Code Section 9.31.025 is the city ADU and JADU ordinance. The City adopted Ordinance No. 2742 on April 24, 2023, and the California Department of Housing and Community Development sent a written findings letter to the City on February 26, 2024 identifying items the Ordinance must amend to align with current state ADU law. ADUs and JADUs are still allowed ministerially, without discretionary review or a public hearing, on any property that includes an existing or proposed single-unit dwelling or a multiple-unit development. The state 60 day clock in Gov. Code 66317(a)(3) still applies, so a completed application that the city does not approve or deny within 60 days is deemed approved.

How long does a Santa Monica ADU permit actually take?

The state clock in Gov. Code 66317(a)(3) gives a permitting agency 60 days from a completed application to approve or deny it, and an application the city does not act on within 60 days is deemed approved. The City of Santa Monica ADU Handbook, dated November 2025 and published on santamonica.gov, is the local document that walks through the local plan check submittal, the corrections loop, and the certificate of occupancy step. L Square prepares the full submittal package and tracks the 60 day clock for the homeowner.

What fees does a Santa Monica ADU pay?

State law in Gov. Code 66311.5(c)(1) says a local agency shall not impose any impact fee upon the development of an ADU that has 750 square feet of interior livable space or less, and impact fees on a larger ADU are charged proportionally to the square footage of the primary dwelling. The City of Santa Monica ADU Handbook, dated November 2025, confirms the same 750 sq ft floor for Santa Monica and lists the Santa Monica-Malibu Unified School District share by name. L Square collects the live fee amounts for the address from the city current application materials before submittal.

How much does an ADU cost in Santa Monica?

L Square publishes configured model prices on the cost guide page: $180,000 for Model 600, $240,000 for Models 800A and 800B, $295,000 for Models 1000A and 1000B, and $354,000 for Model 1200. These are model prices, not a final total for a specific lot. Santa Monica lots also carry the building permit fee, the plan check fee through Building and Safety, the proportional impact fee on ADUs over 750 sq ft under Gov. Code 66311.5, school district fees where the project exceeds the district threshold, and any utility and connection fees from the providers named in the city application materials.

How does the Santa Monica coastal zone change an ADU permit?

Part of the City of Santa Monica sits inside the California Coastal Zone. The City of Santa Monica ADU Handbook, dated November 2025, says the coastal zone generally runs from the beach inland to a city specific boundary on 4th Street and Lincoln Boulevard, and a parcel inside the coastal zone needs an approved Coastal Development Permit from the California Coastal Commission before the City of Santa Monica building permit is approved. ADUs and JADUs themselves are still ministerial under SMMC 9.31.025 and only need a building permit; the coastal review is a parallel requirement for parcels in the coastal zone.

What does state law require every city to allow for an ADU?

State law sets the floor that every California city has to allow for an ADU. Under Gov. Code 66321, a city cannot set a maximum ADU size below 850 sq ft for a studio or one-bedroom ADU, or below 1,000 sq ft for an ADU with more than one bedroom, and cannot require rear or side setbacks greater than four feet for a new construction ADU. Under Gov. Code 66314(d), the city cannot require parking for an ADU within a half mile of a major transit stop or a high quality transit corridor, and ADUs that are converted from existing structures are exempt from the replacement parking requirement. The detached ADU ceiling under Gov. Code 66314(d)(5) is 1,200 sq ft, and Gov. Code 66314(d)(7) waives the setback for an ADU built in the same location and to the same dimensions as an existing structure. A JADU is capped at 500 sq ft of interior livable space under the JADU rules in Gov. Code 66333.

Official Santa Monica ADU sources

• The Santa Monica Topic Explainers page on Accessory Dwelling Units, hosted on santamonica.gov, identifies Section 9.31.025 of the Santa Monica Municipal Code as the city regulation that governs the establishment of ADUs and JADUs in Santa Monica and lists the City of Santa Monica as the publisher of the ADU Handbook for Santa Monica. Official source
• The Santa Monica Preapproved ADU Program page, hosted on santamonica.gov, states that the City has established a Preapproved Accessory Dwelling Unit (ADU) Program allowing vendors to submit standard ADU plans for preapproval without site specific information, that property owners can then select a preapproved standard ADU plan and work with the plan vendor to further develop site specific details and submit for a formal building permit that undergoes an expedited review, and that preapproved standard plans are only permitted for detached ADUs. Official source
• The City of Santa Monica Planning Division page, hosted on santamonica.gov, identifies the Planning Division as the city office that handles ADU and JADU plan check, code compliance, and zoning clearance for properties in the City of Santa Monica at 1685 Main Street, Santa Monica, CA 90401, the same address listed in the HCD ADU ordinance findings letter to the City. Official source
• The City of Santa Monica Building and Safety Division page, hosted on santamonica.gov, identifies the Building and Safety Division as the city office that issues building permits for ADUs and JADUs in the City of Santa Monica, handles plan check, and conducts inspections for residential construction in the city. Official source
• The HCD ADU ordinance findings letter dated February 26, 2024 to the City of Santa Monica, hosted on hcd.ca.gov, states that the City adopted Ordinance No. 2742 on April 24, 2023, that HCD found the Ordinance does not comply with current State ADU Law in the manner noted, that the City must amend the Ordinance to comply, and that the City must provide a written response by March 27, 2024. The letter is addressed to David Martin, Community Development Director, Planning Department, City of Santa Monica, 1685 Main St, Santa Monica, CA 90401. Official source
• Gov. Code 66317(a)(3), hosted on leginfo.legislature.ca.gov, requires a permitting agency to approve or deny the application to create or serve an accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot, and states that if the local agency has not approved or denied the completed application within 60 days, the application is deemed approved. Official source
• Gov. Code 66311.5(c)(1), hosted on leginfo.legislature.ca.gov, states that a local agency, special district, or water corporation shall not impose any impact fee upon the development of an accessory dwelling unit that has 750 square feet of interior livable space or less or a junior accessory dwelling unit that has 500 square feet of interior livable space or less, and that any impact fees charged for an ADU of more than 750 square feet shall be charged proportionately in relation to the square footage of the primary dwelling. Official source
• Gov. Code 66314(d)(5), hosted on leginfo.legislature.ca.gov, states that the total floor area for a detached accessory dwelling unit shall not exceed 1,200 square feet, and Gov. Code 66314(d)(7) states that no setback shall be required for an existing living area or accessory structure or a structure constructed in the same location and to the same dimensions as an existing structure that is converted to an ADU. Official source
• Gov. Code 66321(c)(2)(C), hosted on leginfo.legislature.ca.gov, prohibits any local ordinance that does not permit an accessory dwelling unit with at least 800 square feet of interior livable space and with four-foot side and rear yard setbacks to be constructed in compliance with all other local development standards, and Gov. Code 66321(c)(4)(A) requires every city to allow a height of 16 feet for a detached ADU on a lot with an existing or proposed single family or multifamily dwelling. Official source