ADU Permit Cost & Timeline by City (2026)

A complete ADU permit guide for 2026 — permit costs by city ($1,500–$25,000), plan review timelines (4–16 weeks), application steps, and what documents you need to file. Detailed permit-fee breakdowns for 18 US cities below.

4–16 weeks
Plan review timeline
$1.5K–$25K
Total permit + impact fees
4–10
Inspections per build

ADU Permit Fees by City

Click any city below for the exact 2026 permit-fee breakdown — plan check, building permit, utility hookup, impact fees, and school fees (where applicable).

7-Step ADU Permit Process

1

Pre-application research

Confirm ADU is allowed on your lot (zoning, setbacks, lot coverage). Most cities now allow at least one ADU on any single-family parcel under state pre-emption laws.

2

Design + drawings

Hire a designer/architect or pick a city pre-approved plan ($0–$15K). Drawings must include site plan, floor plan, elevations, structural, and Title 24 / energy compliance.

3

Submit permit application

File building permit application with the city. Pay plan-check fees upfront ($1K–$5K typical). Some cities allow online submission via Accela or eTRAKiT.

4

Plan review + corrections

City planners review for code compliance — typically 4–12 weeks for the first round, 2–4 weeks per correction cycle. Budget 2–3 correction rounds.

5

Permit issuance + fees

Pay full permit fees + impact/utility fees ($4K–$25K depending on city). California cities can no longer charge impact fees on ADUs under 750 sqft.

6

Construction + inspections

Foundation, framing, MEP rough-in, insulation, drywall, and final inspections. 4–10 inspections total over 4–8 months of construction.

7

Certificate of occupancy

Issued after final inspection passes. Required before you can legally rent the ADU.

Frequently Asked Questions

How much does an ADU permit cost in 2026?

ADU permit costs range from $1,500 to $25,000 in 2026 depending on city, ADU size, and whether impact fees apply. Mid-size cities (Denver, Portland, Sacramento) average $4,000–$8,000 in permit fees. California cities cannot charge impact fees on ADUs under 750 sqft — that alone saves $15K–$30K vs pre-2020 fees. See city-by-city permit fee detail below.

How long does an ADU permit take?

ADU permit timelines run 4–16 weeks for plan review, plus 2–4 weeks per correction cycle. California state law (AB 1332, SB 1211) requires cities to issue ADU permits within 60 days of a complete application — though "complete" is interpreted strictly. Pre-approved plan programs in LA, SF, San Diego, Sacramento, and Denver cut review to 2–4 weeks total.

Do I need a permit for an ADU?

Yes — building a habitable accessory dwelling unit always requires a building permit. Unpermitted ADUs cannot be legally rented, cannot be financed against, lower your home appraisal, and create insurance gaps. Many California cities run ADU amnesty programs that legalize existing unpermitted units at reduced fees — see our ADU amnesty programs guide.

What documents do I need for an ADU permit application?

A typical ADU permit package includes: site plan (showing setbacks and easements), architectural drawings (floor plan + elevations), structural calcs, Title 24 / energy compliance, soils report (if required), and a completed application form. Many California cities now accept fully digital submissions via Accela or eTRAKiT portals.

Can I pull my own ADU permit?

Yes — most cities allow homeowner-pulled permits (the owner-builder route) instead of going through a licensed contractor. However, you become personally liable for code compliance and worker injuries, and most lenders will not finance an owner-builder build. For 95% of ADU projects, hiring a licensed contractor is the right move.

Next Steps

Get cost, financing, and builder quotes before submitting your permit.