Resource · Official Sources
The Official California ADU & Building Map
Every claim about an ADU in California eventually traces back to one of these 22 authorities. We've mapped the source documents we cite in plan-check meetings, in financing conversations, and on our own guides — organized so a homeowner can verify anything we say in two clicks.
California State ADU Law & Policy
Statewide rules that override local zoning. Read these first — they define what every city in California must allow.
California Dept. of Housing & Community Development
HCD ADU Handbook & Memos
The state ADU statute (Gov. Code §65852.2), enforcement memos, and the official ADU Handbook PDF.
ADU pricing guide →California Legislative Information
AB 1033 — ADU Condo Conversion
2024 law allowing ADUs to be sold separately from the primary home as condos in cities that opt in.
California Legislative Information
SB 9 — Lot Split & Duplex
Allows up to two units plus a lot split on most single-family parcels statewide.
California Coastal Commission
Coastal Commission ADU Guidance
Coastal Development Permit triggers for ADUs in the coastal zone (Malibu, Santa Monica, parts of OC + Bay).
Malibu permit office →
Building Code & Title 24 Energy
The technical standards every plan check measures against. Citations here are what your architect and inspector argue from.
California Building Standards Commission
2022 California Residential Code (CRC)
Full residential code in force — foundations, framing, egress, fire separation for ADUs.
California Energy Commission
Title 24 Part 6 — Energy Code
All-electric mandate, solar requirements, and battery storage rules for new ADUs and major remodels.
Title 24 climate zones →Department of General Services
CALGreen — Title 24 Part 11
Green building standards — EV charging conduit, water-efficient fixtures, construction waste diversion.
CAL FIRE — Office of the State Fire Marshal
WUI Fire Hazard Maps
Official Fire Hazard Severity Zone maps. Determines Chapter 7A ignition-resistant assembly requirements.
Contractor Licensing & Consumer Protection
How to verify any contractor (including us) and what protections you have if a job goes sideways.
Contractors State License Board
CSLB License Lookup
Confirm a contractor's license status, bond, workers' comp, and complaint history. Verify any bid.
Contractors State License Board
CSLB Homeowner Guide
Plain-language PDF covering contracts, deposits, change orders, and lien releases.
California Architects Board
California Architects Board
Verify an architect's license before they stamp plans for your project.
Rebates, Incentives & Financing
State and utility programs that materially reduce ADU and remodel costs. Stack where eligible.
California Housing Finance Agency
CalHFA ADU Grant Program
Up to $40,000 reimbursement toward predevelopment costs for income-qualified ADU owners.
California Public Utilities Commission
TECH Clean California — Heat Pump Rebates
Statewide incentives for heat pump HVAC and water heaters — required for Title 24 all-electric.
California Public Utilities Commission
Self-Generation Incentive Program (SGIP)
Battery storage rebates — meaningfully offsets backup battery cost paired with solar.
California Alternative Energy & Advanced Transportation Financing Authority
GoGreen Home Energy Financing
Unsecured low-interest loans for HVAC, windows, insulation, and electrical panel upgrades.
Property Tax, Assessor & Title
What an ADU does (and does not do) to your tax basis and recorded title.
California State Board of Equalization
Board of Equalization — ADU Assessment
How county assessors value ADUs. The existing house is NOT reassessed — only the new square footage.
Los Angeles County Assessor
LA County Assessor Portal
Look up your parcel, lot size, current assessed value, and ADU assessment notices.
Santa Clara County Assessor
Santa Clara County Assessor
Bay Area parcel + assessment lookup, including new construction supplemental bills.
Utility Interconnection & Solar
Required filings to power your ADU and to interconnect new solar / battery.
LA Department of Water & Power
LADWP New Service / Solar
Meter spot, service upgrade, and Net Energy Metering applications for LA-proper.
Southern California Edison
SCE Net Energy Metering
NEM 3.0 interconnection for solar + battery in SCE territory (most of LA + Inland Empire).
Pacific Gas & Electric
PG&E Solar & Renewables
Interconnection rules and timelines for Bay Area solar + battery installations.
Southern California Gas Company
SoCalGas New Service
Gas meter installation — only relevant if your ADU is NOT all-electric.