Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in Waldo County, Maine
EPA puts Waldo County in Zone 2, its middle radon zone, and 32.1% of its 209 reported radon tests (2008 to 2017, laboratory totals) 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
32.1%
5.5 pts below ME
- Waldo
- 32.1%
- Maine
- 37.6%
209 tests, 2008 to 2017
Median result
2.3pCi/L
Below action level
- Waldo
- 2.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
209
12th of 16 by tests
- Waldo
- 209
- Cumberland
- 4,076
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Maine
9 of 16
Middle half
- Waldo
- 32.1%
- York
- 48.4%
By share, of 16 with 30+ tests
Read a result for Waldo County
Starts at Waldo County's median, 2.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.3 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. Waldo County's median reported result, 2008 to 2017.
The data
Waldo County, At a glance
Waldo County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Waldo County is a
USGS geologic potential: Moderate across 77% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Waldo County, 2008 to 2017, laboratory
Under 2 pCi/L: 46%2 to 4 pCi/L: 22%4 pCi/L and above: 32%
Of 209 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 97 | 46.4% |
| 2 to 4 pCi/L | 45 | 21.5% |
| 4 pCi/L and above | 67 | 32.1% |
What these figures count
These are the 209 tests reported to CDC for Waldo County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Waldo County, Compared
Waldo County radon figures, compared
Calculated by Radon411In Waldo County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (67 of 209) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 3.6 points lower. Across 16 Maine counties pooled together, 37.6% of tests reached that level, so Waldo County runs 5.5 points below its state.
Of 6 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 4 a smaller one; the spread is 16.4% (Penobscot County) to 39.1% (Hancock County). By share, Waldo County is 9th of 16 Maine counties with 30 or more tests for the same period.
Half the tests came in under 2.3 pCi/L and half over it; the single highest reached 37.7 pCi/L. Below the action level, 97 tests (46.4%) came in under 2 pCi/L, against 41.4% statewide, and 45 tests (21.5%) fell between 2 and 4, against 21.0% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 32.1% share point the same way here. USGS geology rates 77% of the county's land moderate radon potential. CDC also counts 10 tests taken after mitigation in Waldo County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Waldo County went from 176 tests (2005 to 2014) to 209 (2008 to 2017), the share going from 29.0% to 32.1%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Waldo County, Geology
The ground under Waldo County
PredictedMost of the ground under Waldo County is one class on USGS's geologic map: 76.9% of its land is moderate radon potential, with 15.5% high and 5.7% low. The map puts 76.9% of Waldo County in the area it calls Moose River Lowlands/Central Maine Lowlands/Central Maine Highlands/Coastal Province and 15.5% in Coastal Province, with one smaller area beside them. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Moose River Lowlands/Central Maine Lowlands/Central Maine Highlands/Coastal Province | Heterogeneous metamorphic and igneous rocks. | Moderate | 11 | 76.9% |
| Coastal Province | Granite, granodiorite, and mafic metamorphic rocks. | High | 13 | 15.5% |
| Central Maine Highlands | Glacial lake clay and marine clay. | Low | 8 | 5.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Waldo County beside the ground around it
On high-potential ground Waldo County is close to Maine as a whole: 15.5% of its land against 24.5%. Of the 6 counties that border it, 3 have more high-potential ground, Knox County the most at 60.1%.
The map rates the ground, not the air in any home.
Local help
Waldo County, Local resources
Radon testing and mitigation in Waldo County
- Maine Radiation Control ProgramMaine Radiation Control Program, run by Maine Center for Disease Control & Prevention, licenses or certifies radon professionals, and answers questions about testing and mitigation in Maine.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- See the Maine directoryNo professionals are listed in Maine yet. The state program can point you to registered testers and mitigators.
What Maine's program says
- Phone
- 207-287-5676
- radon.dhhs@maine.gov
- Licensing of radon professionals
Under Maine law, only the owner or occupant of a residence or someone registered with the state to provide these services, may test for radon, install and/or advise on the installation of a radon reduction (mitigation) system.
What it means
Waldo County, Questions
Questions about radon in Waldo County
Are radon levels high in Waldo County?
Over the 2008 to 2017 laboratory totals, 32.1% of the radon tests reported to CDC for Waldo County, Maine were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.3 pCi/L. Of 16 Maine counties with 30 or more tests for the same period, 8 reported a higher share; pooled, the state comes to 37.6%.
Which counties border Waldo County?
Waldo County borders 6 counties: Knox County, Kennebec County, Lincoln County, Hancock County, Penobscot County and Somerset County.
Products
Waldo County, Products
Testing a home in Waldo County
In Waldo County, 32.1% of 209 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 37.6% pooled across Maine. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Waldo County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
MonitorAEGTEST
HOUND-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Waldo County, Bordering counties
Counties bordering Waldo County
Calculated by Radon411- Radon levels in Hancock CountyEPA zone 1
39.1%at or above 4 pCi/L
Median 2.6 pCi/L · 327 tests · 7.0 points above Waldo County
- Radon levels in Lincoln CountyEPA zone 1
35.8%at or above 4 pCi/L
Median 2.5 pCi/L · 246 tests · 3.7 points above Waldo County
- Radon levels in Kennebec CountyEPA zone 1
30.3%at or above 4 pCi/L
Median 2.1 pCi/L · 696 tests · 1.8 points below Waldo County
- Radon levels in Knox CountyEPA zone 2
29.6%at or above 4 pCi/L
Median 2.3 pCi/L · 287 tests · 2.5 points below Waldo County
- Radon levels in Somerset CountyEPA zone 1
18.8%at or above 4 pCi/L
Median 1.5 pCi/L · 85 tests · 13.3 points below Waldo County
- Radon levels in Penobscot CountyEPA zone 1
16.4%at or above 4 pCi/L
Median 0.8 pCi/L · 1,491 tests · 15.7 points below Waldo County
Waldo County, Cities and towns
Cities and towns in Waldo County
The Census Bureau estimates 40,693 residents in Waldo County for July 1, 2025, 1,027 more than in 2020 (+2.6%). That works out to 56 people per square mile of land. Belfast, its one incorporated place, has 6,988 residents, 17.2% of the total. Reported testing is thin here: 209 tests over 2008 to 2017, or 5.1 for every 1,000 residents (2025 estimate), where Maine as a whole comes to 8.4.
Belfast is the one incorporated place here; CDC publishes no figure by town, so it reads Waldo County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Belfast | 6,988 | +0.5% | 17.2% |
One incorporated place, 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).
Waldo County, Homes
Homes in Waldo County
Waldo County is a place of houses on their own lots: 75% of its 22,118 homes are detached single-family houses, against 70% across Maine. Half of its homes were built before 1983, close to Maine's 1976: 28% date from before 1960 and 26% from 2000 or later. Owners live in 81% of the occupied homes (Maine: 74%), so for most households a test and a fix are their own to order.
| Homes | Waldo County | Maine |
|---|---|---|
| Housing units | 22,118 | 746,552 |
| Detached houses | 75% | 70% |
| In buildings of 5 or more | 4% | 9% |
| Mobile homes | 13% | 8% |
| Built before 1960 | 28% | 35% |
| Built since 2000 | 26% | 20% |
| Middle year built | 1983 | 1976 |
| Owner-occupied | 81% | 74% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.