ADU Planning Guides
Start here if you are still deciding whether, what and how to build. Each guide answers one planning question with cited local facts.
GuideADU types comparedDetached, attached, garage conversion, JADU and prefab: size, setbacks, cost, timeline, utilities.
1%GuideDoes an ADU raise property tax?Only the new construction is assessed; the land and house aren't reassessed.
$CostADU cost guideCited 2026 ranges by type, all-in components and worked examples.
§RulesADU rules & permitsState law by section, city pre-approved plans, Central San and fire zones.
%IncentivesRebates & financingDated status of SD7, Walnut Creek, Lafayette and CalHFA programs.
BDecisionChoosing an ADU builderCSLB license, deposit cap, bid checklist and red flags.
Next step
Ready to price your ADU?
Share your lot and goals. A local ADU builder can review feasibility and give you a quote.