CA California Porch

ADUs

ADU first-stop check

What to check before a garage, backyard, or spare room becomes a small second home.

Checklist Last reviewed June 30, 2026

Why it matters

State law gives ADUs a strong lane. The address still decides the office, fees, water, sewer, coast, septic, and fire checks.

Directory shelf

Home projects

ADUs, solar, water, wells, sewer, septic, and permit checks.

First moves

  1. 1

    Find the address, parcel number, and city or county.

  2. 2

    Pick the kind of unit: backyard, garage, attached, inside the home, JADU, or a unit in an apartment building.

  3. 3

    Open that city or county ADU page. Save the checklist, fee sheet, and plan list.

  4. 4

    Keep HCD's ADU handbook nearby and compare local rules with the state ADU path.

  5. 5

    Ask what makes the file complete.

  6. 6

    Ask how the 15-business-day complete-file check works.

  7. 7

    Ask how the 60-day yes-or-no clock works after the file is complete.

  8. 8

    Ask early about water, sewer, fire access, power, school fees, impact fees, and utility meters.

  9. 9

    If the home has septic or sits near the coast, call that office first.

  10. 10

    Before hiring, check the license and ask for a written permit plan.

Watch for

  1. 1

    An ADU is not a no-permit job. It is a faster permit lane when the plans fit.

  2. 2

    Local rules need to be clear and written. A vague taste test should not decide it.

  3. 3

    The 60-day clock usually starts after the file is complete.

  4. 4

    If the office says no, ask for the written rule and the missing-item list.

  5. 5

    Small ADUs and JADUs get fee limits. Other plan, utility, school, and permit costs can still show up.

  6. 6

    Coastal lots, old homes, fire areas, hillsides, easements, and septic can add work.

  7. 7

    A cheap design or build quote is not the same thing as permit approval.

Go deeper

Directory paths

Keep moving through the directory.

Use the nearby shelf when this is the right lane, or jump back to the full directory if the task changed names.