Public data transparency

Source-backed data notes for ADU plan records.

ADU Plan Finder organizes public city, county, and state ADU source material into searchable plan, provider, and jurisdiction pages. Each listing links back to official sources whenever available.

Last data refresh Sep 8, 2026

Public dataset

Current public coverage metrics

31,763 city program pages

City program pages

Official city program pages in the current public dataset.

3,078 county context pages

County context pages

County-level pages for broader jurisdiction context.

1,373 canonical plan records

Canonical plan records

Original plan records from the source catalog where each plan comes from.

1,584 accepted-plan listings

Accepted-plan listings

Plan and location pairings shown across city and county pages.

320 providers

Providers

Architects, designers, prefab companies, and public programs in the directory.

57,994 source records

Source records

Official pages, PDFs, catalogs, and provider-linked records reviewed for the public directory.

How the data is organized

One source-backed model for plans, places, and evidence.

Plan pages distinguish the original source record from each place where that plan appears as accepted, so users can follow the public evidence without duplicate plan records.

Locations

Cities, counties, and state context pages used to organize ADU program coverage.

Canonical plans

The original plan records from the jurisdiction or provider catalog where the plan comes from.

Accepted listings

Where a plan is accepted for use. A plan can originate in one city or county and be accepted somewhere else.

Sources

Official city, county, state, PDF, and provider-linked source records used to support plan details.

Current coverage

City program pages

City program pages read the current reviewed public dataset so newly published records stay aligned with the source data.

Data quality principles

Trust rules shown in the public directory

Official sources first

We prioritize city, county, state, and official PDF sources.

Accepted vs. origin logic

Plans are not duplicated just because another city accepts them.

Missing data is shown honestly

If a field is not published by the official source, show "Not listed in source" instead of guessing.

Public corrections welcome

Users can submit corrections or missing official programs.

Known limitations

What the directory cannot guarantee

Official pages can change after the last data refresh.
Some official catalogs do not publish full details like bathrooms, stories, fees, or construction costs.
County-level context does not always mean a plan is accepted inside incorporated cities.
This directory is informational and not permit, legal, architectural, engineering, or construction advice.

Help improve the directory

Send source-backed updates for review.

Report outdated information or point us to an official program that is missing from the current public dataset.

Report a correction

Share a source-backed update for an existing plan, provider, location, or source page.

Report a correction

Submit a missing program

Send an official city, county, provider, or plan source for review.

Submit a missing program