Data · updated Oct 18, 2026

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Name: California ADU fees by city and county
Creator: ADU Fee Map
License: https://creativecommons.org/licenses/by/4.0/

Every modeled fee for every place and size, with the official source, its effective date and the date we checked it. Free to reuse under CC BY 4.0 (opens in new tab): credit “ADU Fee Map” with a link.

adu-fees-totals.csv One row per place and size: low/high totals by category.
adu-fees-lines.csv One row per fee line, place and size, with source URL and dates.
adu-fees.json Everything, including quoted source lines and model inputs.

Assumes a 2,000 sq ft main home and the law in force today. “unmodeled_lines” lists fees that depend on construction valuation or couldn’t be modeled.