ADU guides, page 3
68 guides on what an ADU costs, what the law allows and how to hire well. Every number links to the state law, city page or study it came from.
Design
Carriage house ADU: building an apartment above a garage in California
What a carriage house is, when a garage apartment counts as an ADU, San Diego height and setback rules, fire separation, stairs and costs.
Updated Oct 26, 2026
Real estate
Homes with ADUs: what to check before you buy in California
How to check an ADU's permit, what the seller must disclose, unpermitted units, loans and rent, tenants, an inspection checklist and property tax.
Updated Oct 26, 2026
Prefab
Tiny home ADU in California: when a backyard tiny home is legal
When a tiny home counts as an ADU, tiny homes on wheels, San Diego's movable tiny house rules, permits, utilities and cost.
Updated Oct 26, 2026
Prefab
Amazon tiny home or Home Depot kit: can it be a legal ADU in California?
What online tiny home kits really are, why many aren't permit-ready, how to permit one, real costs and safer alternatives.
Updated Oct 26, 2026
Building
ADU construction: the process step by step, with inspections
What happens at each stage of building an ADU, which inspection closes it, how long the build takes and when to pay.
Updated Oct 26, 2026Building
How to build an ADU in California, from lot check to move-in
The full homeowner path: what your lot allows, ADU type, budget and financing, who builds it, design, permit, build and final inspection.
Updated Oct 26, 2026
Timeline
How long does it take to build an ADU? (2026 San Diego timeline)
Design, the 15-day and 60-day permit clocks, correction rounds, SDG&E hookups, construction and inspections, phase by phase.
Updated Oct 26, 2026Design
ADU design ideas that work within California's rules
Rooflines, small-space interiors, privacy, modern exteriors, fire-zone design, solar and luxury upgrades, built around the rules.
Updated Oct 26, 2026Design
Small ADU guide: studio and 400 sq ft ADUs, costs and fee savings
The fee lines at 500 and 750 sq ft, what small ADUs cost, studio vs one bedroom, what fits in 400 sq ft and tight-lot rules.
Updated Oct 26, 2026
Design
ADU kitchen and bathroom requirements in California
What a legal ADU kitchen and bathroom need, the JADU efficiency kitchen, shared bathrooms and San Diego's rules.
Updated Oct 26, 2026ADU types
Building an ADU in the backyard: what fits, setbacks and cost
How many units fit on your lot, the 800 sq ft guarantee, how close to the fence you can build, access, utilities and San Diego costs.
Updated Oct 26, 2026
Conversions
ADU sheds: can a shed become an ADU in California?
When an existing shed can be converted, the no-setback and 150 sq ft rules, why most sheds fail dwelling code, and what shed-style ADU kits cost.
Updated Oct 26, 2026