Radon levels in Yakima, Washington

ModerateEPA Zone 2

Predicted long-term basement average of 2.0 pCi/L (model estimate) across the 4 modeled ZIP codes in Yakima - close to the US average of 1.8, about 1.3× the Washington average of 1.6. Ranked #3 of 29 Washington cities on this site. Most of the city lies in Yakima County.

Test Yakima, WA - the EPA says "consider fixing" in this range

The predicted basement average here is 2.0 pCi/L, in the 2-4 pCi/L band where the EPA recommends considering mitigation. Plenty of individual homes in a moderate area test above 4. Start with a short-term test; if it comes back at 2 or higher, follow up with a long-term test or a continuous monitor.

Already tested at 4 pCi/L or higher? Find a certified mitigation professional (EPA). A mitigation system typically runs $800-$2,500 installed.

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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.

2.0 ± 0.06

pCi/L predicted basement mean (model SD)

1.1 ± 0.06

pCi/L predicted upstairs (above-ground) mean

2.0-2.0

range of ZIP-level basement predictions in the city

0%

of Yakima ZIPs predicted ≥ 4 pCi/L (50% ≥ 2)

What this means for Yakima

The typical Yakima home is predicted in the 2-4 pCi/L band. The EPA's guidance for this range is to consider fixing, because there is no known safe level and a meaningful minority of homes in a moderate area will test above 4.

The city figure is not a separate estimate: it is the mean of the model's ZIP-code predictions, weighted by the share of the city's land in each ZIP (Census 2020 ZCTA-to-place relationship file). The 1993 EPA zone (2) for Yakima and the 2001-2021 model agree here.

Comparable Washington cities: Vancouver (2.0), Spokane (2.1), Kennewick (1.7), Pasco (1.7).

ZIP codes in Yakima

ZIPs that overlap the city, largest share of its land first. Predicted basement and upstairs means are model estimates; ZIPs the model does not cover show a dash.

ZIPShare of cityBasementUpstairsGrade
9890234%2.0 ± 0.051.0Low
9890833%2.0 ± 0.061.1Moderate
9890118%2.0 ± 0.061.0Low
9890316%2.0 ± 0.061.2Moderate

Testing help in Washington

Washington's radon program page is at doh.wa.gov and, when we checked it, offered a limited supply of free radon test kits. EPA state radon contacts page. If a test comes back at 4 pCi/L or higher, mitigation typically costs $800-$2,500 installed; use EPA find-a-professional and read the mitigation guide.

Yakima radon questions

Is radon high in Yakima, Washington?
Moderate. Averaging the model's ZIP-code predictions across Yakima (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 2.0 pCi/L - close to the US average of 1.8 and about 1.3× the Washington average of 1.6. That is in the 2-4 pCi/L range where the EPA says to consider fixing. Yakima ranks 3 of 29 Washington cities on this site.
Which Yakima ZIP codes have the highest radon?
Predictions for the 4 modeled ZIP codes in Yakima range from 2.0 to 2.0 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 50% at or above 2. The city is fairly uniform, so the city-wide number is a reasonable guide for any neighborhood.
Should I test for radon in Yakima?
Yes, soon. With a predicted basement average of 2.0 pCi/L, a meaningful share of Yakima homes will test above the 4 pCi/L action level. Start with a short-term kit; if it reads 2 or higher, confirm with a long-term test or a continuous monitor before paying for mitigation.
What does EPA Radon Zone 2 mean for Yakima?
Yakima sits mainly in Yakima County, which the EPA classifies as Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and covers whole counties. The 2001-2021 model agrees with the zone for the city. Neither replaces a test of your own home.

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