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Arizona Radon Map and Levels by County

EPA puts all of Arizona's classified counties in Zone 2. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    16.8%

    18.9 pts below U.S.

    Arizona
    16.8%
    U.S.
    35.7%

    3,589 tests across 13 counties, 2008 to 2017

  • Rank among states

    41 of 47

    Ten lowest states

    Arizona
    16.8%
    North Dakota
    59.3%

    By share, every state pooled the same way, 2008 to 2017

  • Counties in EPA Zone 1

    0 of 15

    None at highest potential

    Zone 1
    0
    Zone 2
    15

    Most counties sit in Zone 2; Zone 1 is the highest potential

  • Highest county

    30.0%

    Coconino County

    Coconino
    30.0%
    Mohave
    4.1%

    Counties with 30+ tests, 2008 to 2017

Read a result for Arizona

Starts at EPA's action level

4.0pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.0 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. 16.8% of Arizona's reported tests reached 4 pCi/L, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Arizona, At a glance

Arizona at a glance

Predicted: EPA radon zone

15 of 15 counties classified

EPA classifies counties, not states. Of the 15 counties in Arizona with a zone, 15 are in Zone 2.

  • Zone 2: Moderate predicted potential2 to 4 pCi/L15 of 15 counties · 100.0%

An EPA radon zone predicts a whole county. It is not intended to determine whether any individual home should be tested: homes with elevated levels occur in all three zones, and EPA recommends testing every home regardless of zone.

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

CDC test figures, county by county

CDC publishes Arizona's radon test figures by county: 13 of its 15 counties have one. Each one's share is in the county list.

How to read these figures

Arizona, Compared

Arizona radon figures, compared

Calculated by Radon411
Arizona, 2008 to 2017, laboratory
16.8%
of 3,589 tests at or above 4 pCi/L, pooled
Against the U.S.
−18.9points
35.7% pooled
Rank among the states
41 of 47
1 is the highest share
Counties with 30 or more tests
6
Highest
30.0%
Coconino County
Lowest
4.1%
Mohave County

Fewer reported tests reach 4 pCi/L in Arizona than in most states: 16.8% of 3,589 over the 2008 to 2017 laboratory totals, from 13 counties. Nationally the pooled share is 35.7%: 18.9 points higher than here. Among 47 states pooled the same way it ranks 41st, with Alaska (18.2%) above it and Delaware (16.7%) below.

Coconino County reports the highest share (30.0% of 273 tests) and Mohave County the lowest (4.1%); the most tests came from Maricopa County, 2,393 of them at 17.4%. EPA's 1993 map puts 0 of its 15 classified counties in Zone 1; the tests reported since bear that out at 16.8%.

By band, 1 county at 30% to 50%, 2 counties at 15% to 30%, 2 counties at 5% to 15%, 1 county at under 5%. Across its 4 overlapping ten-year totals, the share went from 17.4% (2005 to 2014) to 16.8% (2008 to 2017), within 2 points, with 2006 to 2015 the highest at 17.6%.

Arizona ranked among 47 states by pooled share of tests at or above 4 pCi/L, 2008 to 2017, laboratory
StateRankCountiesTestsAt or above 4 pCi/L
North Carolina36 of 479973,13922.6%
Alabama37 of 476512,56921.9%
Vermont38 of 471410,60021.7%
South Carolina39 of 474626,48119.4%
Alaska40 of 47983018.2%
Arizona41 of 47133,58916.8%
Delaware42 of 47312,21416.7%
Oklahoma43 of 475281412.7%
California44 of 47569,41510.3%
Texas45 of 471384,61510.2%
District of Columbia46 of 4712,1268.7%
Arizona's highest counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/L
Coconino County1 of 627330.0%
Maricopa County2 of 62,39317.4%
Yavapai County3 of 626516.2%
Pinal County4 of 61018.9%
Pima County5 of 64106.8%
Mohave County6 of 6494.1%
Arizona's counties with 30 or more tests, by their own share at or above 4 pCi/L, 2008 to 2017, laboratory
ShareCountiesTheir testsFor example
50% or more00None
30% to 50%1273Coconino County
15% to 30%22,658Maricopa County, Yavapai County
5% to 15%2511Pinal County, Pima County
Under 5%149Mohave County
Arizona ten-year laboratory totals, pooled, against the United States
PeriodCountiesTestsAt or above 4 pCi/LUnited StatesChange from the row before
2008 to 2017133,58916.8%35.7%+0.2 points
2007 to 2016123,48116.5%35.8%−1.0 points
2006 to 2015123,18717.6%36.3%+0.2 points
2005 to 2014123,04417.4%36.0%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period. CDC publishes no state or national figure.

Arizona, Counties

Arizona counties by EPA zone

Predicted

All 15 counties, grouped by the zone EPA predicts and ordered by their reported share at or above 4 pCi/L, under Arizona's map. Each county has a page of its own.

Arizona radon map by county: EPA radon zones. Map of Arizona's 15 counties shaded by EPA radon zone: Zone 2 in amber. 0 in Zone 1, 15 in Zone 2, 0 in Zone 3.
Arizona radon map by countyEPA radon zones for Arizona's counties: 0 counties in Zone 1, 15 counties in Zone 2, 0 counties in Zone 3.A prediction for each county, not a reading of any home; elevated homes occur in all three zones.

The 6 highest in Arizona, 2008 to 2017

Zone 2: moderate predicted potential15

Local help

Arizona, Local resources

Local resources in Arizona

Who to ask in Arizona: its radon program, test kits and professionals.

What it means

Arizona, Questions

Questions about radon in Arizona

Is radon a problem in Arizona?

Of the 15 counties in Arizona that EPA's Map of Radon Zones classifies, 0 carry Zone 1 (the highest predicted potential), 15 Zone 2 and 0 Zone 3. Pooled from 13 counties, 16.8% of the 3,589 radon tests reported to CDC over the 2008 to 2017 laboratory totals were at or above 4 pCi/L, 41st of 47 states.

Which Arizona counties have the highest radon?

Coconino County 30.0% (273 tests) leads Arizona by the share of reported tests at or above 4 pCi/L, 2008 to 2017, laboratory, then Maricopa County 17.4% (2,393 tests), Yavapai County 16.2% (265 tests), Pinal County 8.9% (101 tests), Pima County 6.8% (410 tests).

Which EPA region is Arizona in?

Arizona is in EPA Region 9: Pacific Southwest.

Products

Arizona, Products

Testing a home in Arizona

16.8% of the 3,589 tests reported to CDC for Arizona over the 2008 to 2017 laboratory totals reached 4 pCi/L: a short-term kit (2 to 90 days) gives a first answer in days, a long-term test the year-round average. A short-term kit (2 to 90 days) is the quick first check for a home in Arizona; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Arizona homes, compared

Explore

Cities in Arizona with their own page

Radon data is published by county, not by city. Each city page sets the figures of the counties the city lies in side by side.