California needs 2.5 million new homes by 2030.
They're already permitted. They're already legal. They're sitting in backyards across the state — invisible until now.
ADUgrade scores every single-family lot in California for accessory dwelling unit potential, using county GIS data, state ADU law, and Claude vision on satellite imagery. We make the hidden supply countable, addressable, and buildable.
Why ADUs are the answer
California has spent a decade trying to build its way out of a housing crisis. New construction takes 5–7 years from entitlement to keys. Multi-family is blocked by lot zoning in most of the state. Building anything net-new requires fighting CEQA, neighborhood politics, and a permitting process that rewards delay.
Accessory Dwelling Units don't have these problems. In 2017–2020 the state liberalized ADU law: California Gov Code §65852.2 now mandates ministerial approval (no public hearing, no design review), allows up to 1,200 sf detached ADUs by right on any single-family lot, waives parking near transit, and caps local impact fees. The barriers are gone. The lots are there.
The remaining problem is discovery. Most homeowners don't know their lot qualifies. They don't know how big a unit could fit, what it would rent for, or how much it would add to their property's value. Real-estate agents don't quote ADU potential on listings. Cities don't promote it. Builders only find leads by cold-calling.
ADUgrade fixes that. We score every California single-family parcel and tell the homeowner what they're sitting on, instantly and for free. Each "A" we surface is a unit that could exist — already permitted, already legal — but isn't because nobody has ever told the owner it's possible.
Every search runs the same scoring pipeline: county parcel geometry · state ADU law · Claude vision on satellite imagery. We count every scored property — qualifying or not — because each one represents a homeowner who now knows their answer.
The four grades, the four outcomes
Every ADUgrade falls into one of four tiers — designed so a homeowner, an agent, or a city planner can read the result in five seconds.
The largest detached ADU the jurisdiction allows (up to 1,200 sf) fits on the lot after setbacks and existing structures. Build today.
A comfortable 2-bedroom footprint (720+ sf) fits. Layout needs care but no fundamental constraints.
A compact detached ADU (400+ sf studio or 1BR) fits. Snug build — or consider attached/junior ADU options for more space.
No detached ADU footprint fits — usually existing coverage, hazard zones, or lot shape. We surface what would need to change.
Sources
- California Government Code §65852.2 — the state law that requires ministerial ADU approval and overrides local zoning that conflicts. Read the statute →
- California HCD Regional Housing Needs Allocation — the official state estimate of housing units needed by 2030. HCD RHNA →
- UC Berkeley Terner Center for Housing Innovation — the leading academic research on California ADU potential, production, and policy. Terner ADU research →
- HCD ADU Handbook & Annual Reports — permit volume and trend data. HCD ADU →
Find out what your lot can do.
One address. Five seconds. Your ADUgrade.
Get my ADUgrade →