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Planning estimate · Bountiful, Utah

ADU design cost calculator

What the drawings cost, and what they buy. Feasibility, concepts, a permit-ready set or a full package — plus the survey, the structural engineer and, for a detached unit in Bountiful, an application to argue as well as a set to draw.

A planning estimate, not a contractor quote. Nothing you enter is sent anywhere.

Feasibility · Concept · Permit setNot a quote
Your estimate

What is behind the number

Read this before you use the number

This is a planning estimate, not a contractor quote. It is built from Utah’s own accessory dwelling unit statute, from Bountiful’s published ADU requirements, and from current Wasatch Front ADU cost data. It cannot see your ceiling height, what your lot does at the back, what the panel can carry, or what is behind the basement wall — and those are the things a real price turns on. Impact fee figures are allowances: Bountiful publishes its own schedule, and it is worth confirming the current numbers with Planning on 801-298-6190 before you budget.

What drives the price

What decides an ADU design fee

ADU design and engineering runs roughly $5,000 to $25,000 across Utah, which is a wide enough range to be useless without knowing what is in it. The variables are the type of unit, how far you need to get, and how much of the existing property has to be measured and drawn before anything new can be drawn against it.

The most useful thing on this page is the cheapest option on it. A feasibility answer — a site visit, a look at the zoning and the services, and a written yes or no — costs a fraction of a permit set and exists to tell you whether to spend the rest. On a Bountiful lot the questions it settles are specific: does the lot clear the buildable-area bar for a detached unit, is there room left under the accessory-footprint limit, does the basement have the ceiling height, and can the services carry a second dwelling.

The other thing worth knowing is that a detached unit needs a case as well as a drawing set. In Bountiful it is a conditional use decided by the Administrative Committee, so part of the fee is an application: a measured site plan, elevations and an argument for how the unit sits on the lot. An internal unit needs none of that.

How far you need to get

Feasibility, concepts, a permit-ready set and a full package with structural and energy are four different products at four different prices. Worth knowing which one a fee quote is for before comparing two of them.

Internal or detached

An internal unit is a permitted use reviewed by staff. A detached unit is a conditional use decided by a committee, which means an application package on top of the drawings and a longer calendar.

Whether the house is already drawn

Most houses are not, or not accurately. Somebody has to measure and draw what is actually there before anything new can be drawn against it, and basements are rarely where the original plans say.

The survey

A detached unit is judged against setbacks, an accessory-footprint percentage and a buildable-area figure. All three are measured from a survey with grades on it, not from a plat printout.

Structural engineering

A separate professional and a separate fee, required wherever load paths change — a new foundation, a floor, a roof, or a header where the garage door used to be.

How settled the brief is

Revisions are the most common reason a design fee lands above its quote, and the most avoidable. Exploring properly is worth paying for on a difficult site; drifting is not.

What pushes it higher

  • A detached unit, which needs a conditional use application as well as a drawing set.
  • A permit-ready set or a full package rather than concepts.
  • No existing drawings, so the house has to be measured first.
  • A steep or bench site needing grading and retaining design.
  • A brief that is still genuinely open.
  • Full stamped structural design.

What brings it down

  • Starting with feasibility only, and stopping there if the answer is no.
  • An internal unit — no application, no committee, a lighter set.
  • An accurate existing survey and existing house drawings.
  • A settled brief and one round of changes.
  • Leaving 3D views and interior selections out.
  • A flat, simple site.

Turn the estimate into a real number

Send a description of the property, roughly what you are picturing, and who the space is for. Every plan starts with your lot — the ceiling height, the fall of the ground and what the services can carry decide more than the floor plan does.

Questions

What people ask about this

How much does ADU design cost?

Roughly $5,000 to $25,000 in Utah for design and engineering, depending on the type of unit and how far you need to get. As a share of the build it usually lands somewhere around 8 to 14 per cent. An internal unit sits at the lower end; a detached unit with a conditional use application at the higher.

What is feasibility, and is it worth it?

A site visit and a written answer on whether the project can happen at all — lot size, accessory footprint, ceiling height, services, setbacks. It costs a small fraction of a permit set and it is the cheapest money on the whole project, because it is the only spend that can save you all the others.

What is in a permit-ready set?

Everything the city needs to issue a building permit: floor plans, elevations, sections, a site plan, and the schedules that go with them. It is not the same as concept plans, which are good enough to price against and to show a lender, but not to build from.

Do I need a survey?

For a detached unit, effectively yes. It is judged against setbacks, a buildable-area figure and an accessory-structure footprint percentage, and all three come off a measured survey with grades on it. For an internal unit it is usually unnecessary.

Do I need a structural engineer?

Wherever load paths change — a new foundation, a new floor, a new roof, an addition tied into the house, or a header where a garage door was. A light internal fit-out that moves no walls may not need one. It is a separate professional with a separate fee, and it is not the place to economise.

What is the conditional use application?

For a detached ADU in Bountiful, the package the Administrative Committee decides on: a measured site plan, elevations, and the case for how the unit sits on its lot and among its neighbours. It is a piece of advocacy as well as a piece of drawing, and internal units do not need one.

How long does design take?

Roughly one to two weeks for feasibility, three to five for concepts, six to ten for a permit-ready set and eight to fourteen for a full package. City review follows: about four to eight weeks for an internal unit, six to twelve for a detached one.

Is this a quote?

No. It is a planning estimate for the design stage. The single biggest thing you can do to keep a design fee at its quote is to settle the brief before the drawing starts.

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