Paper trail
Where our data actually comes from.
Every number on this site has a paper trail. Permit fees and timelines from city portals. Cost benchmarks from HCD data and contractor surveys. Statutes from the California Legislature's bill record. Updated quarterly.
City data
Permit fees, processing windows, impact-fee policies, and notable local rules come directly from each city's planning department portal. Re-verified quarterly (most recently May 2026). Spot a stale number? Email us — corrections in 48 hours.
Cost benchmarks
Per-square-foot build costs for three ADU types at three finish tiers are calibrated against HCD data, the AARP ADU Guide, and recent contractor pricing surveys for the LA-area market. They do not include financing, landscaping, or furniture. Property uplift figures (25–35% of lot value) are based on Fannie Mae appraisal guidance.
2026 law summaries
Statute summaries are plain-language paraphrases of the operative provisions of each cited bill. Citations link to the California Legislature's public bill record. We've focused on bills that materially change the financial or procedural calculus for a typical homeowner.
What we don't independently verify
We don't visit your site, survey your lot, or have inside access to any city's plan-check queue. The dossiers describe the system's published rules; your project's experience depends on people, lot, and timing.