Kootenai County, ID · EPA Zone 1

Radon Mitigation in North Idaho

Across Kootenai County, the share of high radon tests depends on which end of the county you live in. Idaho DHW test results by ZIP code, updated through 2019, show 73% of 320 tests in Spirit Lake at or above 4.0 pCi/L and 46% of 1,328 in Coeur d'Alene's 83814. About one in three county homes stands outside Coeur d'Alene, Post Falls, Hayden and Rathdrum.

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48-hour test from $195 · Systems from $1,295 · Post-mitigation test included

Hillside home above a lake with granite boulders and layered mountains beyond

How it works in North Idaho

STEP 1
Test
A 48-hour continuous monitor in your lowest living level, under closed-house conditions. Report the same day it comes out.
STEP 2
Look and quote
We check the foundation, run a suction test and plan the pipe route for North Idaho winters. You get a fixed price in writing.
STEP 3
Install
Most systems take one day: suction point, sealing, fan, manometer and the electrical permit.
STEP 4
Re-test
A post-mitigation test at least 24 hours after the fan starts shows the new number. The guarantee is below 4.0 pCi/L.

Radon mitigation cost in North Idaho

Four electric utilities serve parts of Kootenai County: Avista, Kootenai Electric, Northern Lights and Inland Power, and your address decides which. Inland Power's Idaho rate couldn't be confirmed, so it doesn't appear here. On rural lots with a crawl space or a manufactured home, a sealed membrane over the soil is usually part of the system.

48-hour radon testfrom $195

Real estate test, tamper-resistantfrom $225

Basement systemfrom $1,295

Slab on grade systemfrom $1,295

Activate an existing passive pipefrom $695

Crawl space systemfrom $1,895

Split-level systemfrom $2,195

Starting prices include the electrical permit and the post-mitigation test. Bold: systems common in North Idaho homes. Estimate your system →

Help paying in North Idaho

Habitat for Humanity of North Idaho, home repair (radon not named, ask): Health and safety repairs for owners up to 80% of the area median income, who help with the work. 208-762-4663
USDA Section 504 Home Repair (radon not named, ask): 1% loans up to $40,000, and grants up to $10,000 for owners 62 or older, for very low incomes in eligible rural areas. Athol and Spirit Lake lie inside USDA's eligible area. Check your address. 208-762-4939
Coeur d'Alene Emergency Minor Home Repair (EMRAP): Grants up to $5,000 for low- and moderate-income owners inside city limits; the city lists radon mitigation systems among its typical projects. 208-769-2382

All programs, and what doesn't pay →

Fan running cost in North Idaho

$49–$67 a year

for a typical 60-watt fan running around the clock, depending on which utility serves your address. Energy charge only, at 2026 residential rates.

Avista Utilities (Idaho) · about 12.7¢/kWh¹⁴$67/yr

Kootenai Electric Cooperative · about 10.5¢/kWh¹⁵Peak Use rate, power cost adjustment included; 11.51¢ on the Traditional rate$55/yr

Northern Lights · about 9.4¢/kWh³²first 950 kWh a month; 11.26¢ above$49/yr

A 20-watt fan costs about a third of that, a 90-watt fan half again as much.

Testing on the prairie, by the lakes and on a well

In 2010 the USGS counted 20.0% of Kootenai County residents on their own water supply, mostly private wells. The Spokane Valley–Rathdrum Prairie Aquifer, Panhandle Health District notes, supplies drinking water to over half a million people in Spokane and Kootenai counties. Idaho's map of well samples with uranium at or above 30 micrograms per liter shows none in the county, but it covers only wells that were sampled.

Idaho DHW normally sends one free short-term kit per address every two years; in October 2026 its shop showed the kit sold out. The state's fallback, the Radon Library Lending Program, has 13 libraries and none in Kootenai County; the nearest are in Plummer, Tensed and Moscow. Panhandle Health District, which serves the county, has no radon program. National Radon Program Services mails a short-term kit for $20 and a long-term kit for $30.

A ZIP share describes hundreds of houses, not yours. Spirit Lake's 73% still left about one tested home in four under 4.0 pCi/L, and 608 of the 1,328 tests in Coeur d'Alene's 83814 came in at or above it. Only a test in your own lowest living space gives your number. The EPA recommends fixing at 4.0 pCi/L or above and considering a fix between 2 and 4.

Two ways to startNo number yet?Book a 48-hour test →From $195, report the day the monitor comes out Tested at 4.0 pCi/L or higher?Get a mitigation quote →Fixed price in writing, post-mitigation test included Or call (509) 278-2215

Permits and local rules in North Idaho

Permits outside cities

Outside city limits, Kootenai County's permit guide sends electrical work to the Idaho Division of Occupational and Professional Licenses (DOPL).¹⁶

Permits inside cities

Post Falls runs its own electrical program: $67 for an existing home with one circuit, plus $10 for each added circuit. Coeur d'Alene's building fee list has no electrical permits, so the state issues them there. For Hayden, Rathdrum and the smaller cities, the issuing office is confirmed before the install.¹⁷

Pipe routing

Unincorporated Kootenai County uses a 24-inch frost depth and minimum flat-roof snow loads by zone: 40 psf in Zone A, 50 in Zone B, 60 in Zone C, engineered in Zone D. These are roof minimums, not ground snow loads.¹⁶

New homes

No Idaho rule requires radon-resistant construction statewide. Kootenai County's building code and the city codes of Coeur d'Alene and Hayden leave the radon appendix out as well, and Post Falls lists the 2018 code without naming an appendix.²⁸

Selling a home

The seller disclosure form in Idaho law has no radon line, only a question about hazardous materials or pest infestations. It rests on what the seller knows, so a test is the buyer's tool.²⁰

North Idaho at a glance

70%

of 636 home radon tests in Athol (83801) at or above 4.0 pCi/L¹

46–73%

of tests at or above 4.0 pCi/L, by Kootenai County ZIP code with at least 300 results¹

1 in 3

Kootenai County homes outside Coeur d'Alene, Post Falls, Hayden and Rathdrum²

+10%

county population growth, 171,362 to 188,323, April 2020 to July 2024³

20.0%

of Kootenai County residents on their own water supply, mostly private wells (2010)⁴

Area figures describe the neighborhood, not your home. Only a test tells you your number. Sources are listed at the end of this page.

Granite edges, deep gravel and two lake outlets

Cretaceous faulting and large granite intrusions shaped the Purcell Trench, the low corridor that runs south from Canada into the Rathdrum Prairie. Granite and gneiss still rise at Rathdrum Mountain and under the uplands around Coeur d'Alene, among mountains that are mostly Belt mudstone and sandstone. A USGS radon assessment flags homes on granite, on gneiss, or in valleys filled with sediment worn from them.

Between those edges, Ice Age floods filled the prairie with gravel hundreds of feet thick, and the water table lies deepest at its north end. In 2004 the USGS measured water levels near Athol more than 540 feet below the surface, the deepest anywhere in the aquifer. The south end is different: the Idaho side's shallowest water lies near the outlets of Coeur d'Alene and Hayden lakes, and near Coeur d'Alene basalt and fine-grained beds, not crystalline rock, border the aquifer.

Idaho DHW's ZIP results lean the same way. Among Kootenai County ZIP codes with at least 300 tests, Spirit Lake and Athol on the northern prairie have the highest shares at or above 4.0 pCi/L, 73% and 70%, while Hayden's 51% and Coeur d'Alene's 52% and 46% come from ZIPs by the lakes. The data don't name a cause, and close to half of the tests in the lowest ZIP still reached the action level.

73% / 46%

of home radon tests at or above 4.0 pCi/L in Spirit Lake (83869) and Coeur d'Alene's 83814¹

Mill towns, orchards and new subdivisions

Lumber built much of the county. After 1900, companies came for white pine and floated logs to sawmills, and towns from Spirit Lake and Twin Lakes to Post Falls and Coeur d'Alene milled on a large scale until the mid-1920s. Athol got its Northern Pacific station in 1882 and declined in the Depression until Farragut Naval Training Station opened in the 1940s.

Dalton Gardens grew cherries, apples and pears, with a packing plant in the 1920s, until a freeze that began on October 31, 1935 killed the cherry trees and many others. Its homes sit on a fan of poorly sorted sandy gravel, 10 to 50 feet thick, spread out below the Hayden Lake outlet. The town incorporated in 1960.

Most of the county's housing is recent. The Census Bureau estimates 80,260 homes in the county, with a median build year of 1996; 43% went up in 2000 or later and 30% before 1980. Mobile homes make up 7.3% of the stock, and about three in four homes are single-family detached houses. Older rural houses with additions, crawl spaces or a manufactured home on the lot get a look at each foundation before a quote.

Basement systems →Slab-on-grade systems →Crawl space systems →Well water →New construction →

When North Idaho homes were built

Before 19507%

1950–197923%

1980–199927%

2000–200920%

2010 or later23%

Share of homes by year built. Source 12.

Towns we serve here

Athol70% of 636 tests at or above 4.0 in ZIP 83801 (Idaho DHW), on the northern Rathdrum Prairie.Book a test in Athol →

Dalton GardensShares ZIP 83815 with north Coeur d’Alene: 52% of 1,928 tests at or above 4.0 (Idaho DHW).Book a test in Dalton Gardens →

North Idaho questions

Why do Spirit Lake and Athol test higher than Coeur d'Alene?

Idaho DHW data show 73% of 320 tests in Spirit Lake and 70% of 636 in Athol at or above 4.0 pCi/L, against 52% and 46% in Coeur d'Alene's two ZIP codes. The data don't say why. The ground changes from the northern prairie to the lake outlets, but each house still needs its own test.

I live outside city limits. Who handles the permit for a radon fan?

Kootenai County's permit guide points electrical work outside city limits to Idaho DOPL. Inside a city it can differ: Post Falls, for one, runs its own electrical program.

My house is on a private well. Should I test the water too?

It's worth asking about. One in five Kootenai County residents drew their own water in 2010, and the state's uranium sample map shows no high wells in the county, though it only includes wells that were sampled.

Is there a free radon test kit in Kootenai County?

Not at the moment: Idaho DHW's free kit was sold out in October 2026, and none of the state's 13 lending libraries are in the county. A short-term kit from National Radon Program Services costs $20.

Does Idaho require radon-resistant construction?

Not statewide. The residential code Idaho adopts omits the radon appendix, so check a newer house for a labeled pipe and test it either way.

What does a radon fan cost to run in Kootenai County?

A 60-watt fan runs about $55 to $61 a year on Kootenai Electric, $67 on Avista's October 2026 Idaho rate and $49 to $59 on Northern Lights. Inland Power also serves parts of the county; its Idaho rate isn't listed here.

Services for North Idaho homes

Radon mitigation Radon testing New construction

Nearby areas

Coeur d'Alene Post Falls Hayden Rathdrum

Neighborhoods and communities we cover

AtholSpirit LakeDalton GardensHauserTwin LakesHayden Lake

ZIP codes: 83801 · 83869 · 83815

Sources for North Idaho (32)

Find your number in North Idaho.

48-hour test from $195. Mitigation from $1,295 with the post-test included.

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