Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Pierce County, Wisconsin
EPA puts Pierce County in Zone 1, its highest radon zone, and 30.9% of its 136 reported radon tests (2023) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
30.9%
4.8 pts below WI
- Pierce
- 30.9%
- Wisconsin
- 35.7%
136 tests, 2023
Median result
2.7pCi/L
Below action level
- Pierce
- 2.7 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
136
37th of 69 by tests
- Pierce
- 136
- Dane
- 2,887
Reported to CDC before any fix, 2023
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Wisconsin
50 of 69
Middle half
- Pierce
- 30.9%
- Langlade
- 65.8%
By share, of 69 with 30+ tests
Read a result for Pierce County
Starts at Pierce County's median, 2.7 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.7 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Pierce County's median reported result, 2023.
The data
Pierce County, At a glance
Pierce County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Pierce County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Pierce County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 46.5% |
| 2015 | 56.2% |
| 2016 | 43.9% |
| 2017 | 31.3% |
| 2019 | 53.1% |
| 2020 | 38.4% |
| 2021 | 44.0% |
| 2022 | 48.0% |
| 2023 | 30.9% |
2023: 30.9%. Across these years the share ran from 30.9% to 56.2%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 136 tests reported to CDC for Pierce County over 2023, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Pierce County, Compared
Pierce County radon figures, compared
Calculated by Radon411In Pierce County, about 3 in 10 reported tests in 2023 (42 of 136) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 2.5 points lower. Across 72 Wisconsin counties pooled together, 35.7% of tests reached that level, so Pierce County runs 4.8 points below its state.
Of 6 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 15.4% (Pepin County) to 49.5% (Goodhue County, MN). By share, Pierce County is 50th of 69 Wisconsin counties with 30 or more tests for the same period.
Year by year, 2014 opened at 46.5% and 2023 closed at 30.9% (down 15.6 points), with 2015 the high at 56.2%. Half the tests came in under 2.7 pCi/L and half over it; the single highest reached 33.8 pCi/L. Below the action level, 40 tests (29.4%) came in under 2 pCi/L, against 41.4% statewide, and 54 tests (39.7%) fell between 2 and 4, against 23.0% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 30.9% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 13 tests taken after mitigation in Pierce County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2014, with 187 tests reported; the quietest, 2022, had 75.
Pierce CountyWisconsin, pooled
| Year | Tests | Pierce County, at or above 4 pCi/L | Wisconsin, pooled |
|---|---|---|---|
| 2014 | 187 | 46.5% | 51.1% |
| 2015 | 162 | 56.2% | 51.6% |
| 2016 | 157 | 43.9% | 45.2% |
| 2017 | 115 | 31.3% | 44.8% |
| 2019 | 81 | 53.1% | 42.9% |
| 2020 | 86 | 38.4% | 27.0% |
| 2021 | 75 | 44.0% | 39.9% |
| 2022 | 75 | 48.0% | 42.9% |
| 2023 | 136 | 30.9% | 35.7% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Pierce County, Geology
The ground under Pierce County
PredictedUSGS's geologic map puts all of Pierce County's mapped land in one class: high radon potential. The map puts 82.1% of Pierce County in the area it calls Western Highlands and 17.6% in Driftless Area. USGS gives both a radon index of 12, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Western Highlands | Glacial deposits derived largely from Ordovician carbonate rocks. | High | 12 | 82.1% |
| Driftless Area | Ordovician carbonate rocks. | High | 12 | 17.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Pierce County beside the ground around it
Pierce County has more high-potential ground than Wisconsin as a whole: 100% of its land against 34.8%. Of the 6 counties that border it, none has as large a share of high-potential ground; Goodhue County, MN comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Pierce County, Local resources
Radon testing and mitigation in Pierce County
Listed radon businesses with an address in Pierce County:
- Wisconsin's radon programWisconsin Department of Health ServicesWisconsin's radon program does not license radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Wisconsin.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
We recommend starting with your regional Radon Information Center since many centers provide test kits for free or reduced cost, and often with laboratory fees covered.
- Compare kits
- Professionals in Wisconsin19 professionals are listed in Wisconsin.
Listed radon professionals by town: River Falls
What Wisconsin's program says
- Phone
- 1-888-569-7236
- DHSRadon@dhs.wisconsin.gov
- Licensing of radon professionals
The State of Wisconsin does not require contractors performing radon measurement or mitigation work to be state licensed or nationally certified.
What it means
Pierce County, Questions
Questions about radon in Pierce County
Are radon levels high in Pierce County?
In 2023, 30.9% of the radon tests reported to CDC for Pierce County, Wisconsin were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.7 pCi/L. Of 69 Wisconsin counties with 30 or more tests for the same period, 49 reported a higher share; pooled, the state comes to 35.7%.
Which counties border Pierce County?
Pierce County borders 6 counties: Pepin County, WI, Goodhue County, MN, St. Croix County, WI, Dakota County, MN, Washington County, MN and Dunn County, WI.
Products
Pierce County, Products
Testing a home in Pierce County
In Pierce County, 30.9% of 136 tests reported to CDC in 2023 reached 4 pCi/L, against 35.7% pooled across Wisconsin. In Zone 1 the year-round level in Pierce County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors3
See every kit and monitor
MonitorINKBIRD
INK-RD3 battery radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Screen
First reading: Within 24 hours
Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Pierce County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Pierce County
Explore
Pierce County, Bordering counties
Counties bordering Pierce County
Calculated by Radon411- Radon levels in Goodhue County, MNEPA zone 1
49.5%at or above 4 pCi/L
Median 3.9 pCi/L · 218 tests · 18.6 points above Pierce County
- Radon levels in St. Croix County, WIEPA zone 1
37.4%at or above 4 pCi/L
Median 3.0 pCi/L · 348 tests · 6.5 points above Pierce County
- Radon levels in Dunn County, WIEPA zone 2
37.4%at or above 4 pCi/L
Median 2.9 pCi/L · 171 tests · 6.5 points above Pierce County
- Radon levels in Dakota County, MNEPA zone 1
34.6%at or above 4 pCi/L
Median 2.9 pCi/L · 2,183 tests · 3.7 points above Pierce County
- Radon levels in Washington County, MNEPA zone 1
21.3%at or above 4 pCi/L
Median 1.9 pCi/L · 1,518 tests · 9.6 points below Pierce County
- Radon levels in Pepin County, WIEPA zone 1
15.4%at or above 4 pCi/L
Median 1.2 pCi/L · 65 tests · 15.5 points below Pierce County
Pierce County, Cities and towns
Cities and towns in Pierce County
The Census Bureau estimates 43,519 residents in Pierce County for July 1, 2025, 1,298 more than in 2020 (+3.1%). That works out to 76 people per square mile of land. River Falls, the largest place on its list (17,916 residents in all), extends beyond Pierce County, so no share of the total is worked out for it. CDC's 136 reported tests for 2023 work out to 3.1 per 1,000 residents (2025 estimate), close to Wisconsin's 3.5.
From River Falls to Maiden Rock, CDC publishes no figure by town: each reads Pierce County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| River Fallsextends beyond Pierce County | 17,916 | +9.9% | Counted whole |
| Prescott | 4,581 | +5.9% | 10.5% |
| Ellsworth | 3,336 | −0.1% | 7.7% |
| Spring Valleyextends beyond Pierce County | 1,443 | +2.9% | Counted whole |
| Elmwood | 805 | −1.0% | 1.8% |
| Plum City | 587 | −1.5% | 1.3% |
| Bay City | 447 | +1.1% | 1.0% |
| Maiden Rock | 118 | +1.7% | 0.3% |
8 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Pierce County is counted whole, so it has no share.
Pierce County, Homes
Homes in Pierce County
Of Pierce County's 17,052 homes, 74% are detached houses, against 66% across Wisconsin; 10% are in buildings of five or more homes. Half of its homes were built before 1980, close to Wisconsin's 1975: 27% date from before 1960 and 26% from 2000 or later. Owners live in 76% of the occupied homes (Wisconsin: 68%), so for most households a test and a fix are their own to order.
| Homes | Pierce County | Wisconsin |
|---|---|---|
| Housing units | 17,052 | 2,750,750 |
| Detached houses | 74% | 66% |
| In buildings of 5 or more | 10% | 17% |
| Mobile homes | 4% | 3% |
| Built before 1960 | 27% | 34% |
| Built since 2000 | 26% | 20% |
| Middle year built | 1980 | 1975 |
| Owner-occupied | 76% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.