Building an ADU in Temecula

Which rules apply in Temecula

Temecula's ADU rules are in Chapter 17.23 of the Temecula Municipal Code, last amended by Ordinance No. 2025-06 on May 27, 2025. The city's ADU page also points to Section 17.06.070, Residential Performance Standards.

The code splits ADUs into two paths:

• Building permit only (Section 17.23.030): ADUs and JADUs that meet the state's by-right rules in Gov. Code 66323, such as a conversion inside the house or an accessory structure, or a new detached ADU of up to 800 sq ft with 4-foot side and rear setbacks. You apply straight to Building and Safety.
• Planning application (Sections 17.23.040-050): other ADUs, reviewed under Gov. Code 66314. The Director of Community Development approves them "ministerially," without a public hearing, and you then apply for building permits.

The city's ADU handout (PL-73, revised January 29, 2026) still says an ADU "cannot exceed 50% of the existing residence or 1,200 square feet (whichever is less)" and that "The property owner must occupy either the primary residence or the ADU." The 2025 code has no ADU owner-occupancy rule, and state law bars one. The code also says size limits can't block an 850 sq ft ADU (1,000 sq ft with more than one bedroom). Rely on the code and confirm with the Planner of the Day at 951-694-6400. [1][2][3][4]

How many units you can build

Under the building-permit-only path, the code lists, for a single-family lot, one ADU and a JADU created inside the house or an accessory structure, and one new detached ADU of up to 800 sq ft, which "may be combined with a JADU." It doesn't say whether the converted ADU and the new detached ADU can both be built on one lot. On multifamily lots it allows converted ADUs in non-living space (up to 25% of the units), up to two detached ADUs with a proposed apartment building, and up to eight detached ADUs (not more than the existing units) with existing apartments.

Under the Planning path, "One ADU shall be allowed on a lot with a proposed or existing primary dwelling that is zoned residential."

HCD's handbook says a city "must allow at least one ADU constructed from existing space, one JADU, and one newly constructed detached ADU" on a single-family lot. If you want all three, confirm with Planning before you design. [1][3]

Size, height and setbacks

Building-permit-only ADUs. A converted ADU or JADU must have exterior access and side and rear setbacks sufficient for fire and safety; a converted accessory structure can expand up to 150 sq ft for entry and exit. A new detached ADU can be up to 800 sq ft with 4-foot side and rear setbacks, 16 feet tall, 18 feet within a half-mile of a major transit stop or high-quality transit corridor (plus 2 feet for a roof pitch matching the house), or 18 feet with a multistory apartment building.

Planning-path ADUs:

• Size: a detached ADU up to 1,200 sq ft; an attached ADU up to 50% of the existing house, or 1,200 sq ft when built with a new house. No ADU smaller than an efficiency unit. The code says these limits can never prohibit "an eight hundred and fifty square foot ADU or a one thousand square foot ADU that provides more than one bedroom."
• Height: detached 16 feet, 18 feet within a half-mile walk of major transit (20 feet for a matching roof pitch), 18 feet with a multistory apartment building; attached 25 feet or the house's height limit, whichever is less.
• Setbacks: 4 feet side and rear; none for an ADU inside an existing structure or rebuilt in the same place and size. The zone's front setback applies unless it would block an 800 sq ft ADU with 4-foot side and rear setbacks, but the code allows a front-setback ADU "only" if building it in the rear or side yard "is entirely infeasible."
• Lot coverage: the zone's limit, except where it would block an 800 sq ft ADU with 4-foot setbacks.
• Separation: 6 feet between a detached ADU and the house, unless that would block an 800 sq ft ADU; not for converted structures.

State law says limits on front setbacks and lot coverage can't block an 800 sq ft ADU with 4-foot side and rear setbacks, and by-right ADUs don't have to meet lot coverage, front setback or design standards. [1][3]

Design, parking and covenants

Design (Planning path). A detached ADU must either use one of the city's Permit Ready ADU designs or use the same materials and colors as the house, and meet any objective design standards for the zone or specific plan. An attached ADU must match the house's materials and colors. Each ADU needs separate exterior access. Fire sprinklers are required only if the house needs them, and an ADU doesn't trigger sprinklers in the existing house.

Parking (Planning path). One off-street space per ADU, on top of the house's parking, except when the ADU is within a half-mile walk of public transit, in an architecturally and historically significant historic district, part of the house or an accessory structure, where on-street permits are required but not offered to the occupant, or within one block of a city-approved car-share space. Parking lost to a garage conversion or demolition doesn't have to be replaced. A JADU needs no parking. State law adds an exemption for an ADU applied for with a new home when another exemption also applies.

Covenants. For a Planning-path ADU, you record a declaration limiting rentals to 30 days or longer and barring separate sale, before the city finals the permit. For building-permit-only ADUs and JADUs, the declaration limits rentals to 31 days or longer, bars separate sale and, if there is a JADU, requires owner occupancy. HCD's handbook, answering whether an affordable housing deed restriction can be imposed on an ADU, says "A local agency cannot impose a deed restriction on an ADU," and notes that state law lets a city require rentals of 30 days or longer. Ask Planning how the city applies the ADU covenant. [1][3]

Fees

City fees. The city's User Fee Schedule for fiscal year 2026-27 lists a $2,232 Planning fee for an Accessory Dwelling Unit application. For a custom ADU up to 1,000 sq ft (grouped with new custom homes), it lists $1,730 building plan check, $2,071 building inspection, $290 fire plan check and $445 fire inspection, $4,536 in total; 1,001 to 2,500 sq ft totals $5,041. The city says fees depend on the path, size, fire sprinklers and grading, and suggests getting estimates from Building and Safety, Fire, Public Works and Planning once you have a concept.

Impact fees. The code says "ADUs that are less than seven hundred fifty square feet shall not be subject to impact fees," and ADUs of 750 sq ft or more pay in proportion to the house. State law exempts ADUs of 750 sq ft of interior livable space "or less," and school districts can charge only ADUs over 500 sq ft.

Other agencies. Check fees with Eastern Municipal Water District (951-928-3777, ext. 2081) or Rancho California Water District (951-296-6900), Temecula Valley Unified School District (951-506-7915), Southern California Edison, SoCalGas, your HOA if any, and Riverside County Environmental Health for septic (951-955-8980). You must give the building official water and sewer service availability letters before the permit. For typical costs see our ADU cost guide. [1][2][3][5]

Junior ADUs

A JADU in Temecula is 150 to 500 sq ft of gross floor area (a shared bathroom doesn't count toward the 500), entirely within the walls of an existing or proposed single-family house; an attached garage counts as part of the house. It needs a separate exterior entry and an efficiency kitchen. It may have its own bathroom or share the house's; without one, it also needs an interior entry to the main living area. No parking is required.

The code says "The JADU or primary residence shall be occupied by the owner of record" unless the owner is a government agency, land trust or housing organization, and you record a declaration barring separate sale and fixing the JADU's size and features. State law changed in 2026: owner occupancy may be required only if the JADU shares a bathroom with the house. If yours has its own bathroom, ask Planning how the rule applies. See our junior ADU guide and garage conversion guide. [1][3]

Renting, addresses and septic

Renting. The city's ADU page says "Short-term rentals (e.g., Airbnb) are not allowed in Temecula, including in ADUs or JADUs." The code limits building-permit-only units to rentals of 31 days or longer and bars Planning-path ADUs from rentals "for less than thirty-one days," while the Planning-path covenant says 30 days or longer. An ADU can't be sold separately unless built by a qualified nonprofit under Gov. Code 66341. You don't have to live on the property to rent an ADU.

Addresses. The code requires an illuminated "Unit 1" on the main house and "Unit 2" on the ADU or JADU. The building submittal handout tells you to request an address 10 days before you submit.

Septic. If the property uses a septic system, check with Riverside County Environmental Health that it can support the ADU; approved septic plans are needed before a permit-ready ADU permit is issued. [1][2][6][7]

Permit Ready ADU plans

The city's Permit Ready ADU (PRADU) plans are "pre-designed plans available for free," though there are fees to submit and build. Five designs are posted: a 499 sq ft studio, a 625 sq ft one-bedroom, a 749 sq ft two-bedroom/one-bath, a 909 sq ft two-bedroom/two-bath and a 1,194 sq ft three-bedroom/two-bath.

Read the PRADU handout first: it walks through HOA review, sewer or septic, electrical and gas upgrades, solar and siting (rear yard, 4-foot side and rear setbacks, zone front setbacks, no easements). It notes that setbacks under 5 feet may need special construction that adds cost. Use the PRADU submittal checklist when you apply. [2][7]

Permit steps in Temecula

1. Check which path your ADU takes

   Compare your plan with Chapter 17.23. If it meets the building-permit-only rules, you apply to Building and Safety; if not, you start with a Planning ADU application. Call the Planner of the Day at 951-694-6400 with questions. [1][2]

2. Get a grading clearance and an address

   Get a clearance from Public Works (951-694-6444), which may require a grading plan before you submit any plans, and request the new unit's address 10 days before submitting. [6]

3. Apply to Planning (Planning-path ADUs only)

   Book an appointment at 951-694-6400 and submit the PL-73 ADU application with site plan, floor plan, elevations, photos, title report and other listed items, plus the filing fee. [4][5]

4. Submit for building permits

   Submit plans online to Building and Safety with the CD-1 building permit application, the CD-18 submittal requirements and the PL-75 ADU tracking form. Fees are due at submittal. [2][6]

5. Get clearances, record the covenant and pull permits

   Provide water and sewer service letters (or septic approval), record the required declaration of restrictions, and pay remaining fees before the permit is issued. [1][6]

6. Build and pass inspection

   Build and pass inspections; the city finals the permit once proof of the recorded covenant is provided. [1][6]

Pre-approved and sample plans

• Permit Ready ADU (PRADU) program

  Five free pre-designed plans (499, 625, 749, 909 and 1,194 sq ft, studio to three bedrooms); you pay permit fees and add site-specific information. [2][7]

Who to call

• City of Temecula Planning Division

  ADU standards, Planning ADU applications (Planner of the Day)

  951-694-6400

  41000 Main Street, Temecula, CA 92590

  [2][4]

• City of Temecula Building and Safety Division

  Building permits, plan check and Permit Ready ADUs

  951-694-6476

  41000 Main Street, Temecula, CA 92590

  [6][8]

• City of Temecula Public Works

  Grading clearance for ADUs and JADUs

  951-694-6444

  [6]

Questions people ask