About

BackyardADU is an independent reference site for California homeowners considering an accessory dwelling unit (ADU).

What we do

We compile public data — the California State License Board (CSLB), the UC Berkeley ADU Scorecard, the Big West Coast ADU Dataset by BuildinganADU.com, and city ordinance text submitted to the California Department of Housing and Community Development — into per-city guides covering ADU cost, zoning rules, permit history, and licensed builders.

What we don't do

• We are not builders or general contractors.
• We do not currently take referral fees or sponsorship from any builder listed in our directory. (If that changes, we will disclose it explicitly on our affiliate disclosure page and on every page where it applies.)
• We do not give legal, financial, or engineering advice. ADU rules vary by municipality and change frequently. Always verify with your local planning department before relying on any figure on this site.

How our cost figures are derived

Cost ranges are based on a regression model grounded in published 2026 builder pricing from sources including Maxable, GreatBuildz, Abodu, Angi, BFPM, and city-specific design-build firms. Per-square-foot ranges reflect all-in design-build pricing (architecture + permits + construction + soft costs). We update the model quarterly. Real builder quotes will always vary — get at least three before signing.

How our zoning information is derived

Each city page lists California state-law minimums (post AB-2221, AB-976, and AB-1033) and links to the city's actual ordinance text on the California HCD website where available. State law preempts city rules in many areas; where cities have stricter or more permissive local rules, we note the linked ordinance for full details.

Contact

Email hello@backyardadu.net with corrections, suggestions, or to flag stale data.