ADU Permit Cost by City: California Fees Compared

The short answer: ADU permit cost differs from city to city in California, but they all follow one state rule: an ADU of 750 sq ft or less pays no impact fees. What differs is everything else, from plan-check and building permit fees to local taxes and school fees. Sacramento publishes line-by-line amounts, San Jose and San Diego publish exemptions and a few fixed fees, and Los Angeles offers a fee calculator. Below is what each city actually publishes, and how to build your own estimate.

Last verified: October 5, 2026 · Written by the ADU Scope editorial team

The four types of fees in your ADU permit cost

• Permit and plan-check fees: the city’s charge for reviewing your plans and inspecting the work. They usually scale with the project’s valuation or size.
• Impact fees: charged by the city and by special districts. In California, an ADU of 750 sq ft or less is exempt. A larger ADU pays fees in proportion to the size of the main home. The state handbook’s example is a 1,000 sq ft ADU behind a 2,000 sq ft house, which could pay up to half the impact fee of a new house.
• School district fees: school districts may charge fees on ADUs of 500 sq ft or more of interior livable space.
• Utility connection fees: an ADU built from existing space, and any JADU, cannot be treated as a new home for water and sewer connection fees unless it is built with a new single-family house. When connection fees do apply, they must be proportionate to the unit’s burden.

ADU permit cost: what each city publishes

City	Impact fees	Other fees we could confirm	Where to get amounts
Los Angeles	None for units under 750 sq ft; proportional above that	No connection fees for state ADUs unless built with a new home	City’s permit fee calculator
San Diego	Exempt under 750 sq ft; subject to impact fees above that	General Plan Maintenance Fee applies to all ADUs, including small ones (a flat $737 per permit application on the city’s current fee schedule; a proposal would replace it with a surcharge on plan-check and permit fees); school fees apply	Fee schedules in the city’s information bulletins
San Jose	School and parkland fees do not apply under 750 sq ft	Building permit fee by size; other process fees may apply	Form 337, Permit Cost Estimate Worksheet
Sacramento	Waived under 750 sq ft	Many line items; see the sample below	Fee estimate form CDD-0419 (revised July 12, 2026)

A sample: Sacramento’s fee estimate form

Sacramento’s form lists the most detail of the four cities. The amounts below are the examples shown on the city’s form and vary with project size and valuation.

Fee	Amount shown on the form
Building permit	$1,267.56 to $1,790.36 (based on valuation)
Building plan review	$532.37 to $751.95 (based on valuation)
Fire plan review	$260.00
Fire inspection	$0.11 per sq ft, minimum $294
Planning review and inspection	$263.00 and $526.00
General plan fee	$2.60 per $1,000 of valuation
Residential construction tax (3+ bedrooms)	$315.00
Park development impact fee	$2,617.50 to $4,188.00
Flood control (SAFCA) fee	$1,575.00 to $2,520.00
Transit mitigation (STA) fee	$1,154.64 to $1,415.76

The same form notes that state law (SB 13) allows most special district fees to be waived for ADUs under 750 sq ft, and that sewer fees, regional sanitation and school fees are paid separately to the county or school district. That is why a single “fee total” rarely matches what owners pay.

How to estimate your own ADU permit cost

1. Start with square footage. At 750 sq ft or less, impact fees are exempt. Under 500 sq ft, school fees are also exempt.
2. Use the city’s official estimator. Sacramento and San Jose provide forms; Los Angeles offers a calculator.
3. Add the pass-throughs. School fees, sewer and sanitation fees are billed by other agencies.
4. Ask in writing. Email the planner and ask which impact fees apply to your unit, and get the answer in writing.
5. Keep a contingency. Review revisions can be billed hourly. Sacramento, for example, lists $216 per hour for additional building review and $263 per hour for planning.

Mistakes that raise your ADU permit cost

Assuming “exempt” means “free”

A 700 sq ft ADU skips impact fees but still pays permit, plan-check, inspection and in some cities flat fees such as San Diego’s General Plan Maintenance Fee.

Counting only city fees

Fees due to the school district, the county sanitation agency and the utility company are separate bills.

Ignoring resubmittals

If your plans come back with corrections, additional review hours add cost. See How Long Does It Take to Get an ADU Permit?.

ADU permit cost: what California law caps

The state rules on fees now sit in Government Code section 66311.5, which older guides and some city pages still cite as section 66324. Sources we reviewed link the renumbering to SB 543, effective January 1, 2026. In summary, as the state housing agency (HCD) describes it in its March 2026 handbook:

• No impact fee on an ADU of 750 sq ft or less, or on a JADU of 500 sq ft or less.
• Above 750 sq ft, the impact fee must be proportional to the ADU’s size compared with the main home. HCD’s formula multiplies the single-family fee by the ratio of ADU square footage to main-house square footage.
• An ADU created within existing space cannot be required to have a separate utility connection or pay connection or capacity fees, unless it is built with a new home or sold separately.
• For other ADUs, a separate connection can be required, and the fee must be proportional to the unit’s burden (square footage or drainage fixture units) and cannot exceed the reasonable cost of providing the service.

ADU permit cost changes to watch: SB 1117 and the 750 sq ft cliff

The line at 750 sq ft can be expensive. On Sacramento’s July 2026 fee form, the examples jump from roughly $5,272 in total at 749 sq ft to roughly $10,624 at 750 sq ft, and about $14,843 at 1,200 sq ft. The statute exempts units of “750 or less,” so ask the city how it treats a unit at exactly 750 sq ft before you design to that number.

A new law aims at that cliff. California YIMBY reported that the Governor signed SB 1117 on September 29, 2026. As described in the Assembly committee analysis of the bill before signing, impact fees would be charged only on the square footage above 750, and the change would apply to the first two ADUs on a parcel. We did not confirm the effective date (new California laws usually start on January 1) and we have not read the chaptered text, so check it before you plan around it.

ADU permit cost in Oakland and San Francisco

Oakland’s fiscal year 2026-27 zoning fee schedule (updated September 4, 2026) lists a line for secondary units and ADUs. The total is $1,061.45: a $878.58 base fee, a $63.26 general plan update charge (7.2 percent) and a $119.61 technology and records charge (12.70 percent). That figure covers zoning review only, not building permits or impact fees, and we could not confirm Oakland’s impact fees for ADUs.

San Francisco does not publish a flat figure. The city says its fees run roughly 6 to 9 percent of construction cost, paid in two installments at filing and issuance. For water and sewer, the SFPUC says that in most cases ADUs pay no additional capacity charges, but it requires a fixture count form. Confirm both with the city.

ADU permit cost in context: what the research shows

Fees are one slice of a much larger bill. UC Berkeley’s Terner Center estimated in its 2020 report that the average ADU in California cost about $167,000 to build, with Los Angeles around $148,000 and the Bay Area around $237,000. Those figures are six years old, so treat them as a scale check rather than a current price. An earlier 2019 Terner Center analysis found that impact fees on new homes in some California jurisdictions could exceed $150,000 per unit, which is the problem the 750 sq ft exemption exists to solve for ADUs.

FAQ

Are fees lower for a garage conversion?

Often. A conversion is usually small enough to fall under the exemptions, and a conversion cannot be charged a new-home utility connection fee. See Garage Conversion to ADU.

Do fees change every year?

Yes. Cities update fee schedules on fiscal-year cycles, so use a current estimate.

Are permit fees part of the construction cost?

They are separate. For build costs, see How Much Does an ADU Cost in 2026?.

Can the city charge an impact fee on a 600 sq ft ADU?

Not an impact fee under the state exemption. It can still charge permit and review fees.

Next steps

• ADU Impact Fees: When You Pay Them and How to Avoid Them
• Los Angeles ADU Rules: Setbacks, Size Limits and Permit Timeline
• San Diego ADU Rules and Fees Explained
• San Jose ADU Requirements: Complete Permit Guide
• Sacramento ADU Rules: What the City Allows
• Do ADUs Need Separate Utility Meters? California Rules and Practical Options

General information, not legal advice. Local rules vary and change; confirm with your planning department.

Sources: HCD ADU Handbook, March 2026 (PDF) · City of Sacramento, ADU Fee Estimate (CDD-0419) · City of San Jose, Fees for ADUs · City of San Diego, ADU fee reinstatement memo (2022) · City of San Diego, Fee Schedule · Los Angeles City Planning, ADU Ordinance · Terner Center, Reaching California’s ADU Potential (2020) · City of Oakland zoning fees FY2026-27 · SF.gov, ADU permits · California YIMBY on SB 1117