
MonitorAEGTEST
HOUND-1011 rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Locations and reports
EPA puts Howard County in Zone 1, its highest radon zone. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
The data
Howard County, At a glance
Predicted: EPA radon zone
This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.
EPA predicts an average indoor
USGS geologic potential: High across 91% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Of 4,549 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 2,260 | 49.7% |
| 2 to 4 pCi/L | 888 | 19.5% |
| 4 pCi/L and above | 1,401 | 30.8% |
CDC publishes this figure only for counties here, so there is no state or national number to compare Howard County, Maryland with.
Distribution of radon tests reported to CDC, not this house. People testing before a sale, or because they suspect a problem, are over-represented in any reported testing data.
The figures at the top are for 2008 to 2017 (laboratory totals): a percentage there is a share of radon tests reported to CDC for Howard County over 2008 to 2017, laboratory, and a percentage in a view below is a share of the tests reported for the year or period it names. It is not a share of homes in Howard County, and it is not a random sample: it counts only the tests people chose to run and that were reported.
CDC works out the shares and the median over pre-mitigation tests, counting a test not marked as before or after mitigation as one of them (4,549 for 2008 to 2017, laboratory). The median is the middle result of those tests, not of buildings. CDC also reports the number of buildings tested (3,429), a different count, so the two totals are not interchangeable.
Howard County's own published CDC figures beside those of the counties that border it, for the same period.
Each figure is that county’s own published CDC figure for 2008 to 2017, laboratory, counting radon tests reported to CDC, not homes. Howard County is this page. Nothing is averaged or combined across counties. The test count beside each county is CDC’s published number of pre-mitigation tests behind its figures. Figures from few tests can swing widely from year to year. Every Maryland county’s own figure is in the Maryland county table.
Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Radon Action Brief
National Radon Action MonthPre-sale
Save 64%Sale price: $8.99Price after the sale: $25Ends Jan 31Then $25Sale ends January 31, then $25
Local help
Howard County, Local resources
Who tests and fixes radon in Howard County: listed businesses, Maryland's radon program and test kits.
Maryland residents may be eligible for a free radon test kit.
What it means
Howard County, Questions
EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. No radon testing business listed on Radon411 has an address in Howard County or names it as a service area yet. The Maryland radon program is the place to ask about certified testers and any test kit offer it runs.
Radon testing: how to test a homeRadon test kits comparedFree and low-cost kits by stateRadon Action Month checklistMaryland radon program
No listed mitigator names Howard County as a service area yet; the Maryland directory lists 5 companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional. Your state radon program is the place to check whether Maryland requires one.
Radon mitigation: how it worksRadon mitigation costRadon mitigation systemsMitigators in Maryland
Over the 2008 to 2017 laboratory totals, 30.8% of the radon tests reported to CDC for Howard County, Maryland were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.0 pCi/L. That is a share of reported tests, not of homes. EPA places Howard County in Zone 1, highest predicted potential, a predicted average indoor screening level greater than 4 pCi/L. Homes with elevated levels occur in all three zones, so the figures describe the area, not your house. Testing is the only way to know the radon level in a specific building.
Radon levels: what a result meansWhat is radon?Radon levels in Maryland
EPA places Howard County, Maryland in Zone 1, which EPA describes as highest predicted potential for the area. A zone is a prediction for the whole county and never determines whether a particular home should be tested. EPA recommends testing every home regardless of zone.
Yes. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. How to test a home.
EPA says short-term tests stay in the home from 2 to 90 days and that all radon tests should run a minimum of 48 hours; long-term tests stay more than 90 days. EPA's guides do not name a best season: they say radon levels tend to vary from day to day and season to season, so a long-term test is more likely than a short-term test to tell you the year-round average.
EPA's Citizen's Guide calls testing easy and inexpensive, and EPA's Home Buyer's and Seller's Guide says passive short-term and long-term devices are generally inexpensive, while active devices may cost more. No national average price is published for this, so Radon411 does not give one. What testing costs.
Howard County borders 6 counties, derived from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county's report can be relevant.
The reported-test figures on this page describe Howard County, Maryland over the 2008 to 2017 laboratory totals. They describe tests other people carried out in other buildings, and none of them measures yours.
What the published data says about Howard County, in words. A zone and a share of tests describe an area, never the level in any one home.
EPA places Howard County in Zone 1, highest predicted potential, as it does 7 other counties of Maryland's 24.
Of the 6 bordering counties, EPA places Baltimore County, Carroll County, Frederick County and Montgomery County in Zone 1 and Anne Arundel County and Prince George's County in Zone 2.
CDC publishes no annual figure for Howard County; its figure is a laboratory total for 2008 to 2017: 30.8% of 4,549 reported tests were at or above 4 pCi/L.
Maryland's radon program and its page are under Local resources.
Products
Howard County, Products
Whatever the figures for Howard County show, only a test tells you about one home.
Test kits and monitors: 1 of 42
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Howard County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Howard County
Testing: 1 of 5
Mitigation: 1 of 3
Explore
Howard County, Bordering counties
counties bordering Howard County: 1 of 6
6 counties share a boundary with Howard County, computed from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county’s report can be worth reading alongside this one.
Howard County, Next steps
What to do next: 1 of 4
Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.