All planning guides

Can your basement become an ADU?

Start with the existing building. A separate kitchen does not by itself establish a legal dwelling.

Inspect the shell before drawing rooms

  • Measure finished ceiling height below beams and ducts, not just at the center of the room.
  • Document water entry, damp walls, drainage and radon concerns. Resolve the cause before covering walls.
  • Have a qualified professional evaluate foundation changes and any proposed window or stair openings.

Plan a safe, comfortable unit

  • Ask the building department which sleeping-room escape openings, stair geometry and exit route apply.
  • Confirm required fire separation, alarms and any shared mechanical-system limitations.
  • Plan sound control at ceilings, plumbing walls and doors. Check ventilation and heating/cooling capacity.

Trace the utility work

  • Locate sewer elevations and determine whether fixtures can drain by gravity.
  • Check electrical panel capacity and where a kitchen exhaust route can terminate.
  • Define responsibility for shared meters, internet, laundry and maintenance access before renting.

Prepare the permit conversation

  • Bring a measured plan showing existing and proposed rooms, entrances and parking.
  • Ask which inspections are required before existing work can be covered.
  • Request a written scope separating repairs, code upgrades, finishes and permit fees.

Turn the checklist into a project plan

Record each open question, the person responsible, evidence needed and target date. Confirm requirements with the city and your licensed design/build professionals.

Find your city guide · Prepare a budget · Discuss this checklist at my free review

Planning guidance. Requirements depend on the property, design and adopted local codes; this guide does not certify compliance. How our guidance is prepared