ADU Builder in Wildomar, CA: Pre-Approved Plans, Permits and Costs

What ADU size, height and setback rules apply on a Wildomar lot?

The city's 2026 ADU Guidebook lists the standards it applies to a single-family property: 1 ADU plus 1 JADU, a detached unit of up to 1,200 sq ft, an attached unit at 50 percent of the primary dwelling or 1,200 sq ft, whichever is less, a height of 16 ft as the standard and 25 ft as the maximum, and side and rear setbacks of no more than 4 ft. A new attached or detached unit built within the existing living area or inside an accessory structure needs no setback at all. An ADU that replaces an existing garage or storage structure in the same location and to the same dimensions needs no setbacks either. A JADU stays at 500 square feet or less of interior livable space. If the primary dwelling has fire sprinklers, the ADU needs them as well.

Does the City of Wildomar have free pre-approved ADU plans?

Yes. The city owns six pre-approved ADU plans and posts them for use at no charge: Plan 1 Studio at 493 sq. ft., Plan 2 One Bedroom at 646 sq. ft., Plan 3 Two Bedroom A at 749 sq. ft., Plan 4 Two Bedroom B at 1,139 sq. ft., Plan 5 Three Bedroom A at 994 sq. ft., and Plan 6 Three Bedroom B at 1,195 sq. ft. The city also runs a Pre-Approved ADU Program, called PRADU, where a designer submits construction documents for city pre-approval and then adapts the approved design to your address. The city says those plans are only about 80 to 90 percent complete, so every homeowner still works with the designer on the site-specific changes.

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

The city's 2026 ADU Guidebook says a complete plan check typically takes about two weeks and is required to take no more than 15 days, and that the city must issue a final decision within 60 days of the application. On a plan built from the city's pre-approved designs, the review path is shorter: the PRADU process caps pre-approval at 60 days and site-specific review at 30 days. Applications go in electronically and the building counter does not take them. Inspections are scheduled Monday through Thursday, and construction hours run Monday through Saturday from 6:30 am to 7:00 pm. State law sets the backstop: the city must say in writing whether the application is complete within 15 business days, must approve or deny a complete application within 60 days, and a complete application the city has not acted on in that time is deemed approved.

What does an ADU permit cost in Wildomar?

The building permit is priced from the project valuation. The city's building permit valuation fee sheet sets a base permit fee from the ICC construction valuation, then adds a building plan check at 75 percent of the base, a development review at 20 percent of the base, and general administration at 15.58 percent of the base. The plan check fee has to be paid before any review starts. The planning fee schedule for FY2026-27 took effect on July 1st 2026 with a 3.43 percent increase, and each extra plan check adds a fee equal to 25 percent of the original fee. Impact fees are the part that surprises people. The city's 2025 development impact fee schedule charges fees per dwelling unit for new residential development, with a single-family residential total of $22,230.00 per unit, but state law stops the city from charging impact fees on an ADU of 750 sq ft or less, and on a JADU of 500 sq ft or less. A larger unit is charged in proportion to the primary dwelling.

How much does an ADU cost in Wildomar?

L Square publishes configured unit prices for its prefab models: $180,000 for Model 600, $240,000 for Model 800A and $240,000 for Model 800B, $295,000 for Model 1000A and $295,000 for Model 1000B, and $354,000 for Model 1200. These are configured unit prices, not a final project total for a house nobody has seen. A Wildomar quote also carries the site work your lot needs, such as grading, a drainage plan, utility connection work and structural engineering, and the city wants a water and sewer will-serve letter or a county approval for a well or septic system before the permit is issued.

What should I check on my Wildomar lot before building an ADU?

Start with water and sewer. The city asks for a will-serve letter from Elsinore Valley Municipal Water District, or approval from the Riverside County Department of Environmental Health for a well or septic system. Then line the plan up against your site: setbacks of no more than 4 ft from the side and rear lot lines, a height of 16 ft as the standard and 25 ft as the maximum, and parking of no more than one space per unit or per bedroom. If the primary house has fire sprinklers, your ADU needs them. One more item matters if you have been reading an older Wildomar ordinance: in a letter dated December 5, 2025, the state housing department said the most recent ADU ordinance on file for the city is from 2020 and may be out of date with state law, and it asked the city for a response by January 4, 2026.

Official Wildomar ADU sources

• The City of Wildomar owns six pre-approved ADU plans and posts them for use at no charge: Plan 1 Studio 493 sq. ft., Plan 2 One Bedroom 646 sq. ft., Plan 3 Two Bedroom A 749 sq. ft., Plan 4 Two Bedroom B 1,139 sq. ft., Plan 5 Three Bedroom A 994 sq. ft., and Plan 6 Three Bedroom B 1,195 sq. ft. Official source
• The city's Pre-Approved ADU Program (PRADU) lets designers submit construction documents for pre-approval. City staff approves or denies a pre-approval in no longer than 60 days and then reviews the site-specific aspects of the plans in no longer than 30 days. The city says the pre-approved plans are only about 80 to 90 percent complete and always need property-specific modifications, and it requires a water and sewer will-serve letter from Elsinore Valley Municipal Water District or approval from the Riverside County Department of Environmental Health for wells and septic systems. Official source
• The city's 2026 ADU Guidebook states that a complete plan check typically takes about two weeks from the time of submittal and is required to take no more than 15 days, that the city must provide a final decision within 60 days of submitting the application, and that a single-family property may have 1 ADU plus 1 JADU, a detached unit of up to 1,200 sq ft, an attached unit at 50 percent of the primary dwelling, a height of 16 ft standard and 25 ft max, setbacks of no more than 4 ft from the side and rear lot lines, and parking of no more than one space per unit or per bedroom. Official source
• The city's Building and Safety Department tells applicants to expect a 12-month timeline for an application for plan review or permit, made up of an initial 180 days plus two 90-day extensions as outlined in the California Building Code, and that no further extensions are granted beyond that period. The department lists the 2025 California Building Code, 2025 California Residential Code and 2025 California Fire Code among its current code adoptions, and states that applications are submitted electronically because the counter does not accept them. Official source
• The city's 2025 development impact fee schedule, updated 07-01-25 with a 5.56% construction cost index increase, lists a single-family residential total of $22,230.00 per dwelling unit, made up of fee lines for transportation roads, signals, police facilities, fire protection, park land and improvements, community center, city hall, corporation yard, multi-purpose trails, animal shelter and a DIF administration fee, with separate totals for multi-family, commercial, office, industrial and business park land uses. Official source
• The city's FY2026-27 Planning Fee Schedule took effect July 1st 2026 with a 3.43% increase. It states that fees are based on 2-3 plan checks and approval of plans or reports, and that for each additional plan check a fee equal to 25% of the original fee will be due. The schedule lists a Pre-Application Review (PAR) application fee of $5,816.00 and a Setback Adjustment (Administrative Review) application fee of $1,320.00. Official source
• The city's building permit valuation fee sheet derives the base permit fee from the ICC construction square footage valuation using a permit fee multiplier of 0.00909, then builds the total permit fee from a building plan check at 75% of the base, a development review at 20% of the base, and general administration at 15.58% of the base, plan check, and development review combined. It also lists a miscellaneous hourly plan review fee of $188.77. Official source
• In a letter dated December 5, 2025, the California Department of Housing and Community Development advised the City of Wildomar that the most recent ADU ordinance on file with the department is from 2020, and that given the changes to state ADU law since then the ordinance may be outdated and out of compliance with state ADU law. The letter asks the city for a response by January 4, 2026, and notes that under Gov. Code Section 66326, subdivision (d) an ordinance that is null and void leaves the city applying state ADU law only, while Section 66316 makes a noncompliant ordinance null and void. Official source
• California Government Code Section 66317 provides that a permitting agency shall approve or deny an accessory dwelling unit application within 60 days from the date it receives a completed application, that if the agency has not approved or denied the completed application within 60 days the application shall be deemed approved, and that if the applicant requests a delay the 60-day period is tolled for the period of the delay. It also requires written notice of completeness no later than 15 business days after the application is received. Official source
• California Government Code Section 66314 provides that the total floor area for a detached accessory dwelling unit shall not exceed 1,200 square feet, that an attached accessory dwelling unit shall not exceed 50 percent of the existing primary dwelling, that a setback of no more than four feet from the side and rear lot lines shall be required, that parking requirements shall not exceed one parking space per unit or per bedroom, and that the local agency shall not require replacement parking spaces for any garage, carport or parking structure converted into an accessory dwelling unit. Official source
• California Government Code Section 66311.5 provides 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