A neutral navigator for California’s ADU surge. Pick your city, get the rules. Tune your build, get the cost band. Read the 2026 law changes that just rewrote what’s possible on a multifamily parcel.
Permit fees, build cost band, realistic timeline, the rule that catches most owners off guard, and a direct link to the city planning portal. Approximate values, citable sources at the bottom.
Estimates synthesize city fee data with state-wide $/sq ft benchmarks. Treat the band as a planning tool, not a quote — bid the build to confirm.
A typical detached ADU on an unremarkable parcel. Add weeks for coastal review, historic districts, hillside grading, or sewer-lateral upgrades.
Lot survey, setback read, choosing a stock plan vs. custom. Most surprises that kill a project are caught here.
Architect or pre-approved plan provider produces the full permit set. Title 24, structural calcs, energy compliance.
City review, corrections, revisions. Pre-approved plans often clear in half this window. Coastal/historic adds.
Foundation, framing, MEP rough-ins, finish. Where the calendar can blow up if a sub goes sideways.
Building, electrical, plumbing, mechanical, final. Certificate of Occupancy. Utility meter set if separate.
First tenant, family member, or short-term-rental setup. Property reappraisal triggers here.
A multifamily-lot owner. A homeowner facing a $30k utility-upgrade demand. An HOA member who’d been told no. All three got new rights this year.
FHFA tracked CA homes from 2013–2023. Properties with an ADU appreciated at 9.34%/yr. Without, 7.65%/yr. A 1.7-point delta compounds into six figures over a decade.
An 800 sq ft detached unit in most CA metros rents for $2,200–$3,800/mo, depending on neighborhood. Garage conversions clear the same ranges at half the build cost.
Aging parents. Adult kids. Home office. Long-term rental. Med-term furnished rental. The same envelope serves four life stages. Few other capital improvements do.
A 40-page PDF: every Top-25 California city scored, every fee verified against the city portal, every 2026 statute annotated with what it changes for whom. We’ll email you when it’s ready — no other use, no resale.
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