Allowed use
Confirm whether the unit can be rented, used for family, or occupied as a long-term residence.
REGULATIONS
Know the questions before you commit to the design.
ADU rules vary by location and change over time. Use this guide to organize your research and conversations with local authorities.
THE SIX-PART CHECK
A practical framework for property research.
The answer is not one zoning number. Feasibility usually comes from several rules working together.
Maximum size
Local rules may set a floor-area cap, lot-coverage limit, or relationship to the main home.
Setbacks
Review rear, side, street and fire-separation distances before choosing a footprint.
Height & stories
Detached and two-story ADUs may follow different height, privacy, and daylight rules.
Parking
Requirements can depend on transit proximity, unit type, bedroom count, and local exemptions.
Utilities
Plan electrical capacity, sewer or septic, water, stormwater, and any separate metering.
PROPERTY READINESS NOTES
Bring this checklist to the planning counter.
Record the exact code section, official source link, date checked, staff contact, and any property-specific interpretation.
Estimate after researchOFFICIAL STARTING POINTS
Verify the rule with the agency that applies it.
California HCD explains the state framework; city planning and building departments apply current requirements to the parcel and plans.
Important
This concept does not provide parcel-specific legal conclusions. Always verify current rules with the official municipality or authority having jurisdiction and consult qualified design, engineering, legal, tax, and construction professionals where appropriate.