Money
What does it cost to build a custom home in St. Anthony, Idaho?
Published · every figure below was checked against its primary source on the date shown.
Nobody local publishes a number, and that is honest
Search for what it costs to build here and you will find figures. Almost none of them were produced by anyone who has built in Fremont County; they are statewide or national averages wearing a local place name.
The builders here do not publish prices, and it is not evasion. On this ground the same house can cost meaningfully different amounts depending on what the site turns out to require, and a published rate would be wrong more often than right. What follows is what can be stated: the public costs that are knowable in advance, and the variables that actually decide the rest.
The public costs, by side of the line
| Cost | Inside city limits | Outside, in the county |
|---|---|---|
| To have the application accepted | $150 deposit | A deposit is due on submittal |
| Site plan review | Not separately stated | $50, and charged again if you revise approved plans |
| Building permit fee | Based on square footage and construction type | Based on square footage and construction type |
| Water and sewer | Hookup fees, paid before permit approval | — |
| Septic | — | Permit required at submittal, from Eastern Idaho Public Health |
| Sidewalk, curb and gutter | Required before certificate of occupancy, scaling with your frontage | Not required |
| Access | — | Driveway permit for new access to a county road or highway |
| Engineering | Submittal by a registered design professional | Stamped plans for free-standing post & beam; engineer or architect at the county's stated snow-load threshold |
Two observations from that table. The city front-loads money into the application; the county front-loads it into testing the ground. And the sidewalk line has no county equivalent at all — it is a genuine difference in what the same house costs on either side of a boundary.
One of those county lines is worth quoting exactly, because it is the only published figure in this whole area that most people never hear about until they trigger it a second time:
“Site Plan Review: An accurate, detailed site plan is required for all building permits. A $50.00 fee will be charged for the site plan review. If you bring your plans back for a change after approval, you will be charged an additional site plan review.”
— Fremont County, Pre-Construction Check List for Building Permits, rev. 17 April 2026. Retrieved 14 August 2026
Fifty dollars is not what makes that worth knowing. The re-charge on revision is: it prices indecision, and it is the county telling you plainly that changing approved plans is a fresh transaction rather than an amendment.
What actually moves the number
Site work, and it is not close. Everything below is unknown until somebody tests it, and each one can move a budget by an amount that dwarfs every fee in the table above.
- Well depth. Not knowable until drilled. Price it as a range and hold a contingency.
- The septic system the ground will accept. The site evaluation decides this, and a standard system and a complex alternative system are different orders of cost.
- Access and earthwork. How far, over what, and how much has to move.
- The finish level. The single largest controllable variable, and the one where two bids most often turn out to be pricing different houses.
The snow load is a real input and a modest one. At 50 PSF this district carries the county's lowest design figure, which eases the roof structure relative to higher-load districts and — subject to confirming the county's 70 lb/ft² sentence — may keep a conventional build below the point where an engineer or architect must design it. Worth having. Not the thing that decides your budget.
Five questions that make bids comparable
- Is site work a fixed price or an allowance? If it is an allowance, what is the allowance and what happens when it is exceeded?
- Which public fees are inside your number? Permit, hookups, site plan review, septic, driveway, sidewalk. Name them individually.
- What is your exclusions list? In writing. This is where two bids stop being the same house.
- What allowances are you carrying, for what, and at what figure? Two builders carrying different flooring allowances are not quoting the same job.
- Who is providing stamped plans, and is that cost in your number or mine?
Most of the gap between two bids in this valley is scope, not margin. Force the scope to match and the comparison usually becomes obvious.
Where to start
Before you ask anyone for a price, settle the two facts that determine which column of the table above you are in and how big the unknowns are: which side of the city limits the parcel is on, and what the ground will take. City of St. Anthony, 420 N Bridge Street Suite A, St. Anthony, ID 83445 — (208) 624-3494; inspections (208) 709-3030, 24 hours' notice; Fremont County Building Department, Fremont County Courthouse, 151 W 1st North, St. Anthony, ID 83445 — (208) 624-7200.
Or send the parcel and the rough idea to (208) 656-1745 and you will get a straight read on which costs apply to you — from someone with nothing to sell you.
Related reading on this site
- St. Anthony issues its own building permits — the boundary that decides half the costs on this page
- The St. Anthony District snow load is 50 PSF — the one design figure that can remove an engineering line item
- Building a barndominium in St. Anthony — where stamped plans become a mandatory cost rather than an option
Common questions
What does it cost to build a custom home in St. Anthony, Idaho?
No local builder publishes a price per square foot, and any single number you see quoted for this town came from somewhere else. What can be stated honestly are the fixed public costs on each side of the city line, and the variables that actually move a bid.
Why will nobody give a price per square foot?
Because on this valley floor the site work and the finish level swing wider than the shell does. A figure that averages a city infill lot with a rural build on untested ground is not information — it is a number that will be wrong for both.
What are the fixed public costs I can actually plan for?
Inside the city: a $150 deposit before the application is accepted, building permit fees based on square footage and construction type, water and sewer hookup fees, and sidewalk, curb and gutter along your frontage. Outside: a deposit on submittal, a $50 site plan review fee, a septic permit, and a driveway permit if you are creating new access.
What moves a bid the most?
Site work, almost always. Well depth, the septic system the site evaluation requires, access, and how much earth has to move. Those are unknown until tested, which is exactly why testing early is worth what it costs.
Does the low snow load make building here cheaper than up the valley?
It can reduce roof structure cost relative to a higher-load district, and it may — subject to confirming with the county — keep you below the threshold at which an engineer or architect must design the structure. Neither of those is the biggest line in your budget. Site work is.
How do I make two bids comparable?
Force them onto the same scope. Ask each builder to price the same allowance schedule, list their exclusions explicitly, state which public fees they have included, and say whether site work is a fixed price or an allowance. Most bid gaps are scope gaps.
Should I get three bids?
Get three if three builders here will genuinely bid your project, and be realistic that a good local builder may be booked. Three comparable bids beat five incomparable ones. The comparability is the work.
Is it cheaper to build in town or out in the county?
Neither reliably. The city front-loads known fees — a deposit, hookups, and sidewalk along your frontage — while the county front-loads unknowns you have to test, chiefly the well and whatever septic system the ground will accept. A city lot is more predictable; a county lot has a wider range in both directions.
Ask about a build in St. Anthony
Describe the parcel and roughly what you have in mind. What comes back is an honest read on which firms here take that kind of work, plus the one thing most people have not established yet: whether the city or the county will be reviewing your plans. Free, and nothing automated ever follows.
- Say where the ground is and what you intend to put on it.
- You are pointed toward the firms in this town with that work behind them.
- From there it is between you and them. No commission, no introduction fee, and nobody standing between you and your own contract.
One contact method is plenty — whichever you prefer. A human being writes back.