Permit guides

ADU Permits in Davis: a Homeowner's Guide

The city's pre-designed plans, the 1,000 sq ft threshold that changes your review path, and how the process works — in plain language.

Last updated October 2026. Rules change; always confirm current requirements with the city before you build.

Who handles your permit

In Davis, ADU permits run through the city's Community Development Department. Davis is unusual in one important way: under Municipal Code Section 40.26.460, a detached ADU over 1,000 square feet requires an Administrative Use Permit — a separate approval with a 10-day public comment period and written notice to properties within 500 feet. Stay at or under 1,000 sq ft and you avoid that entire step.

What you can build

1,200 sq ftMax for a detached ADU under state law

1,000 sq ftAbove this, Davis requires an Administrative Use Permit

4 ftMinimum side and rear setbacks, detached ADUs

16 ftHeight limit for most detached ADUs

1 + 1One ADU plus one Junior ADU per single-family lot

60 daysState deadline to act on a complete application

Davis's pre-designed ADU program

The city publishes three pre-designed ADU plans made available to homeowners: a studio at 300 sq ft, a one-bedroom at 612 sq ft, and a two-bedroom at 742 sq ft, each in three exterior styles — Adobe, Agrarian, and Mid-Mod. The plans still go through the city's typical review for your specific project, but starting from a city-developed design removes a large chunk of the design risk.

The 1,000 sq ft line matters. If your plans show 1,050 sq ft, you've just added a use-permit process, a comment period, and neighbor notices. Designing at 1,000 or below keeps the project on the ministerial track.

What goes into the submittal

Building permit application to the Community Development Department
Site plan with setbacks, easements, and utility locations
Floor plans, elevations, and structural details
Title 24 energy compliance documents
Electrical, plumbing, and mechanical layouts

Where applications usually get stuck

Crossing the 1,000 sq ft threshold unknowingly. Gross vs. net square footage confusion has pushed projects into use-permit review.
Older housing stock. Davis has many mid-century homes; garage conversions often surface foundation, electrical, and ceiling-height issues.
UC Davis rental dynamics. High rental demand means many ADUs are investment-driven — size the unit for the local market before you design.
Incomplete energy documents. Missing Title 24 forms are a perennial first-round correction.

Not sure where to start? That's the part we do. We check your property against Davis's requirements, coordinate the plans and specialists, and manage the submittal and corrections — one point of contact.

Tell us what you need help with.

Not sure where to start? That's what we're here for.

Send your project

Erik — (916) 540-8960 · Vall — (916) 956-8106
office@pcg-engineering.pro