ADU Builder in Temecula, CA: Permit-Ready Plans, Permits and Costs

What are the ADU size and setback rules in Temecula?

Temecula's Planning Division handout, form PL-73 (revised 01/29/26), says an ADU cannot exceed 50% of the existing residence or 1,200 square feet, whichever is less, and cannot be smaller than a 150 square foot efficiency unit. The design must match the existing residence in materials, mass and landscaping, and the unit has to comply with Chapter 17.23 of the Temecula Municipal Code plus the residential performance standards in Section 17.06.070. The city's Permit Ready ADU handout places a permit-ready unit in the rear yard with 4 foot rear and side yard setbacks and the front yard per zoning, and warns that setbacks under 5 feet can trigger special construction requirements. State law sets the floor under those local rules: local rules cannot block a unit with at least 800 square feet of interior livable space and four-foot side and rear yard setbacks, and a detached ADU cannot exceed 1,200 square feet of floor area.

How long does the City of Temecula take to review an ADU permit?

Temecula runs two paths. If the project meets the submittal requirements in Chapter 17.23.030 of the Temecula Municipal Code, it goes straight to the Building and Safety Division as a Building Permit Only case. Everything else starts with a Planning application, and only after Planning approval can you submit to Building and Safety. Public Works weighs in before plans go in: a grading plan clearance may be required first, and a new address has to be requested 10 days before submission. The state clock still applies on top of that. Government Code Section 66317 gives the agency 15 business days to say whether an application is complete and 60 days from receipt of a complete application to approve or deny it, and an application the city has not acted on within 60 days is deemed approved. For the permit-ready route the city's handout lays out six steps, from plan research through city review, permit, clearances and final inspection.

How much does the City of Temecula charge for an ADU permit?

The FY 2026-27 user fee schedule prices a custom ADU up to 1,000 square feet at $4,536 in total citywide fees: $1,730 for building plan check, $2,071 for building inspection, $290 for fire plan check and $445 for fire inspection. A 1,001 to 2,500 square foot custom ADU comes to $5,041, and a 2,501 to 5,000 square foot one comes to $6,908. The Planning Department charges $2,232 for an Accessory Dwelling Unit application, and a simple project carries a $142 permit issuance and administrative fee plus $73 for each extra inspection trip. Impact fees sit outside that total. State law bars any impact fee on an ADU of 750 square feet or less and on a junior ADU of 500 square feet or less, and anything larger is charged in proportion to the primary dwelling. School district, water district and septic fees are billed separately by those agencies.

How much does an ADU cost in Temecula?

L Square's configured prefab model prices are $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 configured model prices, not final project totals. A Temecula lot adds its own line items: utility laterals, sewer or septic work, grading and foundation work. The city's own paperwork shows where those costs come from. Public Works may require a grading plan clearance before plans are accepted, and a soils and geotechnical report is required for any ADU over 500 square feet. A permit-ready plan can also move money around, because the city supplies the drawings.

What should I check before building an ADU in Temecula?

Start with what the parcel already has. If the home sits on sewer, Eastern Municipal Water District sends a sewer clearance to the city's Building and Safety Department before a permit-ready ADU permit is issued. If the lot uses a septic system, approved septic plans from Riverside County Environmental Health come first, and those plans can decide where the unit fits. Check the lot coverage question in the city's Permit Ready ADU handout before you pick a plan above 800 square feet. Check your HOA before you design, since the city's handout lists HOA review among the outside reviews that affect the timeline. Finally, plan for the ground: the city's Building and Safety handout lists a wind speed of 97 MPH, wind exposure C, climate zone 10 and seismic design category D.

Official Temecula ADU sources

• The City of Temecula publishes five free Permit Ready ADU plans: Studio (499 square feet), 1 Bedroom/1 Bathroom (625 square feet), 2 Bedroom/1 Bathroom (749 square feet), 2 Bedroom/2 Bathroom (909 square feet) and 3 bedroom/2 Bathroom (1,194 square feet). The city states that Permit Ready ADUs are pre-designed plans available for free, that there are fees for submitting and building your PRADU, that short-term rentals are not allowed in Temecula including in ADUs or JADUs, and that ADU and JADU standards sit in Chapter 17.23 and Section 17.06.070 of the Temecula Municipal Code. Official source
• City of Temecula Planning Division handout PL-73, revised 01/29/26, states that the square footage of an ADU cannot exceed 50% of the existing residence or 1,200 square feet, whichever is less, that ADUs cannot be smaller than an efficiency unit of 150 square feet, that the design shall match the existing residence in materials, mass and landscaping, that parking requirements must be met under Section 17.24.040, and that additional requirements are in Section 17.06.050 of the Temecula Municipal Code. Official source
• City of Temecula handout CD-18, revised 02/06/26, states that ADUs and JADUs meeting the submittal requirements in Chapter 17.23.030 of the Temecula Municipal Code may submit directly to the Building and Safety Division, and that all others must submit a Planning application first. It lists the 2025 California Building Code and the other 2025 Title 24 codes, a wind speed of 97 MPH, wind exposure C, climate zone 10, seismic design category D, that a new address must be requested 10 days prior to submission, and that a soils report is required for ADUs larger than 500 square feet. Official source
• City of Temecula handout CD-70 on the Permit Ready ADU program, revised 07/20/23, sets out six steps from plan research through build and inspect. It says a permit-ready ADU sits in the rear yard with 4 foot rear yard setbacks and 4 foot side yard setbacks, with front yard setbacks per zoning, that setbacks of less than 5 feet may require special construction requirements, and that lot coverage must be checked above 800 square feet. A sewer clearance from Eastern Municipal Water District reaches the city before permit issuance. Official source
• The City of Temecula User Fee Schedule effective fiscal year 2026-27 prices a new custom ADU up to 1,000 square feet at a total citywide fee of $4,536.00, made up of $1,730.00 building plan check, $2,071.00 building inspection, $290.00 fire plan check and $445.00 fire inspection. A custom ADU of 1,001 to 2,500 square feet is $5,041.00 total and 2,501 to 5,000 square feet is $6,908.00 total. The Planning Department lists an Accessory Dwelling Unit fee of $2,232.00, and the permit issuance administrative fee for a simple project is $142.00 with $73.00 for each additional trip. Official source
• California Government Code Section 66317(a)(2)(A) requires a permitting agency to determine whether an accessory dwelling unit application is complete and give written notice of that determination no later than 15 business days after receiving the application. Section 66317(a)(3) requires the permitting agency to approve or deny the application within 60 days from the date it receives a completed application, and states that if the local agency has not approved or denied the completed application within 60 days, the application shall be deemed approved. Official source
• California Government Code Section 66321(b)(3) states that no local lot coverage, floor area ratio, open space, front setback or minimum lot size rule may be applied 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. Section 66321(b)(4)(A) requires local agencies to allow a height of at least 16 feet for a detached accessory dwelling unit. Official source
• California Government Code Section 66314(d)(5) states that the total floor area for a detached accessory dwelling unit shall not exceed 1,200 square feet, and Section 66314(d)(4) states that the total floor area for an attached accessory dwelling unit shall not exceed 50 percent of the existing primary dwelling. Section 66314(d)(7) provides that a setback of no more than four feet from the side and rear lot lines shall be required for an accessory dwelling unit that is not converted from an existing structure. Section 66314(d)(10)(A) limits parking to one space per unit or per bedroom. Official source
• California Government Code Section 66311.5(c)(1) 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 accessory dwelling unit with more than 750 square feet of interior livable space are charged proportionately in relation to the square footage of the primary dwelling unit. Official source