Search “ADU cost Los Angeles” and you get a range wide enough to be useless. The honest version: a permitted backyard unit in the Valley is a small house. It has a foundation, a wet wall, a roof, and a path through plan check. Paint is the cheap part.
Owners who get surprised are usually surprised by the tap, not the tile.
Where the money actually goes
Utility tie-in, waterproofing, and inspection sequencing eat more of the bid than the Instagram finish. A studio with a kitchenette and a shower is a different animal than a one-bedroom with a full kitchen — because both drain, and one of them drains a lot.
If the lot already has a clean sewer lateral with slope, you are in a better story than a pad that needs a new tap across the driveway.
A useful way to think about it
Price the wet rooms and the permit path first. Then pick finishes. Reversing that order is how a “simple ADU” becomes a second construction loan.
We will tell you on the first visit if the lot wants an ADU or if a conversion is the smarter tool. That conversation is free. The surprise later is not.
Written for homeowners in San Fernando Valley. CSLB #1120118.
