Is radon high in Mercer County, New Jersey?

Low. The model predicts a long-term basement average of 1.3 pCi/L in Mercer County (about 26% below the US average of 1.8 and close to the New Jersey average of 1.3). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 8 of 21 New Jersey counties.

Should I test for radon in Mercer County?

Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Mercer County already range from 0.8 to 2.1 pCi/L. A short-term kit costs little and settles the question for your house.

What does EPA Radon Zone 1 mean for Mercer County?

Zone 1 - highest potential (predicted average > 4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.3 pCi/L does not line up with Zone 1, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.

How much does radon mitigation cost in Mercer County?

A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; New Jersey quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

Radon levels in Mercer County, New Jersey

LowEPA Zone 1

Predicted long-term basement average of 1.3 pCi/L (model estimate) across 20 ZIP codes - about 26% below the US average of 1.8, close to the New Jersey average of 1.3. Ranked #8 of 21 New Jersey counties.

Test Mercer County, NJ once anyway - radon varies house to house

The predicted basement average here is 1.3 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.

Get a short-term test kit →Or track it with a continuous monitor

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Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.

1.3 ± 0.06

pCi/L predicted basement mean (model SD)

0.9 ± 0.07

pCi/L predicted upstairs (above-ground) mean

0.8-2.1

range of ZIP-level basement predictions in the county

What this means for Mercer

The typical Mercer County home is predicted below 2 pCi/L, the lowest band. That is the best case an area can show - but it describes the average house, and the ZIP-level predictions within the county still span 0.8 to 2.1 pCi/L.

Note that the EPA classifies Mercer County as Zone 1 while the newer model predicts 1.3 pCi/L. The zone map predates two decades of test data; where they disagree, we grade on the model but show both. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable New Jersey counties: Middlesex County (1.3), Gloucester County (1.3), Cape May County (1.4), Burlington County (1.3). The state's highest is Warren County at 2.3 pCi/L.

ZIP codes in Mercer County

Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.

ZIP	Basement	Upstairs	Grade
08540	1.6 ± 0.06	1.3	Low
08618	1.5 ± 0.06	1.0	Low
08648	1.6 ± 0.06	1.2	Low
08610	1.0 ± 0.07	0.7	Low
08611	0.8 ± 0.07	0.6	Low
08520	1.3 ± 0.06	0.9	Low
08638	1.5 ± 0.06	1.1	Low
08619	1.2 ± 0.06	0.9	Low
08550	1.3 ± 0.05	0.8	Low
08690	1.2 ± 0.05	0.8	Low
08691	1.3 ± 0.05	0.8	Low
08620	1.3 ± 0.06	0.9	Low
08609	0.9 ± 0.07	0.6	Low
08534	1.8 ± 0.05	1.4	Low
08629	0.8 ± 0.08	0.6	Low
08628	1.7 ± 0.05	1.3	Low
08542	1.4 ± 0.06	1.1	Low
08525	2.1 ± 0.05	1.5	Moderate
08560	1.8 ± 0.06	1.3	Low
08608	0.9 ± 0.07	0.6	Low

If your test comes back at 4 pCi/L or higher

Mitigation is a routine job: a fan-driven pipe that vents soil gas from under the slab to above the roofline, typically $800-$2,500 installed (typical range; local quotes vary). Use certified professionals: EPA find-a-professional. Read the full mitigation guide.

Mercer County radon questions

Is radon high in Mercer County, New Jersey?: Low. The model predicts a long-term basement average of 1.3 pCi/L in Mercer County (about 26% below the US average of 1.8 and close to the New Jersey average of 1.3). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 8 of 21 New Jersey counties.
Should I test for radon in Mercer County?: Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Mercer County already range from 0.8 to 2.1 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 1 mean for Mercer County?: Zone 1 - highest potential (predicted average > 4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.3 pCi/L does not line up with Zone 1, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
How much does radon mitigation cost in Mercer County?: A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; New Jersey quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

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