Turnkey ADU: What's Included and What Isn't (2026)

The short version

“Turnkey” should mean one contract, one price, one team that takes your ADU from first drawing to the keys, design, engineering, permits, utilities, build, and finishes included.
The costs that usually sit outside it: financing, furniture and appliances beyond spec, extensive landscaping, and genuine site surprises (handled as documented allowances, not buried).
Turnkey is often not more expensive than piecing it together, because it removes the coordination gaps where change orders live.
The test of a real turnkey quote is whether design, permits, utilities, and finish level are itemized, vague lump sums hide gaps.

What does “turnkey” actually mean for an ADU?

Turnkey means you turn the key at the end and everything in between was handled for you. In practice, that is the difference between hiring an architect, then an engineer, then an expediter to chase permits, then a general contractor, and coordinating all of them yourself, versus signing one contract with one company that owns the whole process. The second path is what we mean by a turnkey ADU, and it is the model that keeps a project on budget, because no one can point at someone else when something falls between the cracks.

What a turnkey ADU includes

Included in a turnkey ADU	Usually outside the contract
Architectural design & structural engineering	Financing (we point you to RenoFi)
Zoning research & all permits (filed for you)	Furniture, decor, and appliances beyond the agreed spec
Site prep, foundation & utility connections	Extensive landscaping beyond the build footprint
Full construction, interior & exterior finishes	HOA approvals (we prepare what you need to submit)
Inspections through the certificate of occupancy	Genuine site surprises (handled as a documented allowance)

The part that separates a real turnkey builder

Two things. First, the permits: a genuine turnkey builder files and manages every approval, the Fairfax County PLUS portal, Montgomery County DPS, or the DC Department of Buildings, so you never stand in a permitting line. If you want the detail, our Fairfax County ADU permit process guide walks through it step by step. Second, honesty about the unknowns: site conditions like septic capacity or a long utility run are not always visible on day one, and the right contract names them as allowances up front rather than pricing them at zero and billing you later.

Questions to ask any “turnkey” builder

Are design and structural engineering included, or billed separately?
Who files the permits, me or you?
Are utility connections and site work in the base price?
What finish level does the price assume, and what are the allowances?
How are change orders handled, and what triggers one?

If the answers are clear and in writing, you have a turnkey builder. If they are vague, you have a low number that will grow. That is also the heart of comparing ADU bids.

Frequently asked questions

What does a turnkey ADU include?

A true turnkey ADU bundles design, structural engineering, permits, site preparation, utility connections, the full build, interior and exterior finishes, and final inspections through the certificate of occupancy, all under one contract with one price and one project manager.

What is usually NOT included in a turnkey ADU price?

Financing, furniture and decor, extensive landscaping beyond the build footprint, and true site surprises, such as a septic upgrade only discovered once testing is done, which a good contract handles as a documented allowance or change order rather than hiding it.

Is turnkey more expensive than hiring trades separately?

Often it is not. Bundling design, permits, and construction under one contract removes the coordination gaps between an architect, an expediter, and a general contractor, which is where change orders and delays usually come from. You also get a single point of accountability.

Do I still have to deal with the county myself?

No. A genuine turnkey builder files and manages the permits for you, whether that is the Fairfax County PLUS portal, Montgomery County DPS, or the DC Department of Buildings, and carries the project through inspections to the certificate of occupancy.

How do I know a turnkey quote is actually complete?

Look for design, engineering, permits, utility connections, and a defined finish level as line items, not one vague lump sum. If those are missing, they usually reappear later as change orders. Comparing what is included, item by item, is the real test.

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