Detached ADU cost in Woodland Hills comes down to five things on your own lot: the size of the unit, the foundation under it, how far the utilities have to travel, how a crew gets equipment to the back of the yard, and the fire and sewer rules that apply to the address. Our base is in Woodland Hills, so a lot visit here is a short drive. Below, each of those lines is set out for a freestanding unit, so the written quote you get from us reads clearly. The one figure we publish is the plans package for a qualifying one-story ADU up to 500 sq ft, starting at $8,350 with construction priced separately.
A freestanding unit on a Valley lot
A detached ADU is a complete small house. It has its own footings, walls, roof, kitchen, bathroom and electrical service. Nothing is borrowed from the main house except the connections. That is why it carries more lines than a conversion or a JADU, and why the lot decides so much of the number. Many back yards on inland valley lots are open enough for a unit, but a pool, a mature tree, a slope at the rear or a long driveway can each change where the unit sits and what it takes to reach it.
If you already have a spot in mind, send the address and a few photos of the yard. We walk the lot and then send a written quote with every line priced.
What sets the price of a detached ADU
Size and layout. Floor area matters, but the room count matters more. A second bathroom or a full kitchen adds plumbing, venting and cabinets that do not shrink with the square footage. A studio and a two-bedroom unit on a similar footprint can land far apart.
Foundation. A flat pad with firm soil takes a standard slab or a raised floor. A sloped rear yard can call for a soils report, deeper footings or a short retaining wall. We price the foundation after we have seen the grade, never before.
Utility runs. Sewer, water and power travel from the house or the street to the new unit. Every foot of trench is a cost, and so is whatever sits on top of the route: a patio, a driveway, planting. If the electrical panel has no spare room, an upgrade goes on its own line.
Site access. Concrete, lumber and the soil from the trench all have to move through the yard. A side yard wide enough for a small loader keeps the work simple. A narrow gate means more work by hand and more days on site.
Fire and sewer rules. Requirements vary by address, so we check with the building department for this lot. That can include a rated wall when the unit sits close to a property line, a review of fire access to the back of the parcel, and where the new drain may tie into the sewer lateral. If the unit sits lower than the lateral, a pump may be needed.
Plans. Drawings, structural calculations and the energy forms are their own line. For qualifying small one-story ADUs, a plans package is available, and it appears as a separate line on page one of the quote.
Choices that change the scope
Some decisions move the total more than any finish choice. Placing the unit near the house shortens the trench but costs privacy. Pushing it to the rear corner gives a tenant a separate path but lengthens every connection. A loft or a second story adds stairs, structure and a taller review. A separate electric meter makes renting simpler and adds utility company work. Clearing an old shed or slab first adds demolition and haul off.
If you are finishing a unit someone else started, or need one part redone, we will still look at it and price it. Most owners who call us, though, are pricing a full new unit from footing to final, and the quote is laid out for that.
How the visit and written quote work
The first step is a visit to the lot. We walk the yard, measure distances to the property lines, find the sewer cleanout, open the panel and check the path from the street. Then we sketch where a detached unit can go and how large it can be.
The written quote follows that visit. Each line from the list above is priced on its own: plans, permits and fees, site work and foundation, utility connections, the shell, interior finishes. A line that depends on something we cannot see yet, such as the depth of the lateral, is marked and paired with how we will check it. When you compare quotes, you can hold ours next to another and see which items the other one left out.
LADBS reviews the plans for a Woodland Hills unit and inspects the work through final. We prepare the set, answer the plan check comments and keep the file moving until the permit is issued.
What to have ready for the visit
A few things make the first visit faster and the quote tighter:
- The property address and, if you have one, a survey or an old site plan.
- Photos of the back yard, the side yards and the electrical panel with its cover on.
- The size and room count you have in mind, even roughly.
- Whether the unit is for family or for rent, since that affects the meter and the layout.
- Any old permits or drawings for the house or the garage.
None of this is required. It simply lets us mark fewer lines as unknown.
Our ADU construction page compares all four unit types, and our structural work page covers foundations and retaining walls on harder lots. If the household needs more room rather than a second home, see room additions. Notes on the city itself are on our Woodland Hills page.
Ready to price your unit
Call us or send the form with the address and a few yard photos. We will set a time to walk the lot, then send a written quote with each line priced for a detached unit.