Project field guide
ADU
Accessory dwelling units are housing, not sheds. Expect zoning, building, energy, fire, parking, and utility review. State law (especially in California) has opened the door in many cities — it has not removed the permit.
Permit complexity
High
Typical band
$120,000–$450,000
Unit
per ADU
2026 U.S. typical range; coastal metros sit higher. Estimates, not bids.
Start with two separate questions
Always. Budget months, not weekends.
Reduced ADU setbacks exist in some states (e.g. 4 ft side/rear patterns in parts of California). Confirm the version that is in force.
What usually decides the scope
- Detached, attached, or conversion
- Owner-occupancy rules
- Size caps and rear-yard limits
- Separate utility meters
- Fire access and sprinklers
State vs. city
Some states pre-empt local bans. That does not pre-empt building code, utility capacity, or fees. Read both layers.
Use the dimensions, not a guess
Related field notes
Primary sources
What this page was checked against
- Residential Plan Review
City of Austin Development Services · checked 2026-09-02
Used for: Austin residential small-project and plan-review entry points.
- Zoning Search and ZIMAS
Los Angeles City Planning · checked 2026-09-02
Used for: Property-specific zoning and overlay lookup in Los Angeles.
- Producer Price Indexes
U.S. Bureau of Labor Statistics · checked 2026-09-02
Used for: National input-price context; not a local contractor quote.
These sources establish examples and market context; they do not make a city-specific determination for your property.
Requirements vary by jurisdiction and by the specifics of a project. YardPermit publishes educational patterns and labeled estimates — not legal determinations, not construction documents, and not a bid. Verify with your local building department and a licensed contractor before you build.