Ask anything about building codes and zoning
Cited answers from Title 24, the state housing laws, and the local code of 540 California cities & counties.
See full coverage — every California jurisdiction, Title 24, and the state housing laws.
What is GoCodebook?
GoCodebook is an AI research assistant for California building codes, zoning, and housing law. Ask a question about any property and get a plain-English answer with the exact controlling citation — drawn from the California Building Standards Code (Title 24), the statewide housing laws, and the local zoning ordinance for that city or county.
Architects, contractors, developers, planners, and homeowners use it to check what they can build before they commit: setbacks, height limits, FAR, lot coverage, ADU and JADU rules, SB-9 lot splits, change of use, permits, and rent control. Every answer links to the verbatim code text in the Code Library, so you can read the controlling section yourself.
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Code Library
The verbatim enacted text of 794 California codes, ordinances, and statutes, section by section.
Title 24 Building Codes
All 13 parts of the California Building Standards Code, explained in plain English.
Housing & Tenant Laws
Rent control, evictions, ADU law, and the statewide housing statutes.
Zoning by City
Zoning and planning-code guides for 480+ California cities.
Zoning by County
Regulation guides for all 58 California counties.
ADU Rules by City
The state-law baseline plus each city's local ADU requirements, compared side by side.
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Frequently asked questions
What is GoCodebook?
GoCodebook is an AI research assistant for California building codes, zoning, and housing law. Ask a question about any property and get a plain-English answer with a citation to the controlling code section — drawn from the California Building Standards Code (Title 24), the statewide housing laws, and the local zoning ordinance for that city or county.
Which codes and cities does GoCodebook cover?
All 13 parts of the California Building Standards Code (Title 24, 2025 edition), the statewide housing laws — including ADU law, SB 9, and rent control — and local zoning for 540 California cities and counties. The Code Library holds the verbatim text of 794 codes and ordinances, more than 289,000 sections. Coverage is California-only today. See full coverage.
Is GoCodebook free to use?
Reading and searching the Code Library is free with no sign-up. AI answers are metered: three free answers without an account, then one cited answer per day on a free account. Paid plans start at $15/month — see pricing.
How accurate are GoCodebook's answers?
Every answer is grounded in the verbatim code text and cites the controlling section, with a link into the Code Library so you can read the original language yourself. AI can make mistakes, which is why every citation is verifiable — see the methodology for how answers are grounded and what the review dates mean.
Does GoCodebook replace a permit review or professional advice?
No. GoCodebook is a research tool that shows you what the adopted codes say so you start informed. Final code determinations rest with your local building department, and project-specific decisions should be verified with a licensed professional.