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Informational only — not legal or financial advice.
ADU Explorer is an editorial field guide. We work hard to keep our data accurate, but every project is different and every city's rulebook drifts. Treat this site as a starting point — not a substitute for talking to the people whose job it is to say yes or no.
What this site is
ADU Explorer publishes researched, editorial summaries of California Accessory Dwelling Unit (ADU) law, city-by-city permit fees and timelines, and an interactive cost estimator. Our goal is to help homeowners walk into their first contractor conversation with a working mental model.
What this site is not
This site does not provide:
- Legal advice. Statutory interpretations and citations are summarised for plain-language reading. They are not a substitute for a licensed California attorney's review of your specific situation.
- Financial advice. Cost estimates, rent projections, and property-value uplift figures are based on aggregated market data. They are not appraisals, tax forecasts, or investment recommendations.
- An engineering opinion. Feasibility on your specific lot depends on soils, slope, easements, overlays, and existing structures — none of which we can see from a planning portal.
- A guarantee of permit approval. Even a perfectly compliant application can be delayed, conditioned, or denied. Plan-check is a human process.
Verify with your city
Every city dossier on this site links to the official planning portal. Before you commit time, money, or a contract to anything, open that portal and re-check the fee schedule, processing windows, and any local overlays that apply to your address. Fees drift annually; rules occasionally change mid-year.
Cost figures are estimates
Our cost bands reflect 2026 LA-area pricing for typical ADU projects. Your actual cost will depend on contractor selection, finish choices, site conditions, financing terms, and timing of materials purchases. Treat our numbers as a project envelope — not a bid.
Sponsored partner disclosure
We may earn a referral fee from listings clearly marked SPONSORED · PARTNER. Editorial content (city dossiers, law summaries, cost benchmarks, FAQ) is never sponsored and never altered by partner relationships. If we wouldn't recommend a partner to a friend, we don't list them — fee or no fee.
Liability
To the maximum extent permitted by law, ADU Explorer and its operators disclaim all liability for losses arising from reliance on this site's content. Use the information here as one input among many; the final call is always yours.
Questions or corrections
If something on this site looks wrong, please email us via the "Talk to us" form. We update city data quarterly and fast-track any reported errors.