State rankings
Radon Levels by State
Alaska has the highest Average Radon Level (10.7 pCi/L), followed by South Dakota (9.6 pCi/L) and Pennsylvania (8.6 pCi/L). Louisiana has the lowest (1.1 pCi/L).
Average Radon LevelBetter directionWhether a higher or a lower value is better. A green arrow means higher is better, a red arrow means lower is better, and no arrow means neither.More in the glossary →
50 of 51 statesAverage Radon Level
Darker means higher. Click a place to highlight it.
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All 50 ranked
Highest first.
Distribution Median and middle halfThe median is the middle value: half of places are above it, half below. The middle half is the range holding the central 50% of places.More in the glossary →
Each dot is one state; the lines mark the median and the middle half.
Median
4.4 pCi/L
Middle half 3.2 pCi/L – 5.9 pCi/L
Average
4.6 pCi/L
50 states
Highest
10.7 pCi/L
Alaska
Lowest
1.1 pCi/L
Louisiana
Data
Click a column to sort, a row to highlight that place on the charts.
50 states · # = rank by Average Radon Level
| # | ||
|---|---|---|
| 1 |  Alaska | 10.7 pCi/L |
| 2 |  South Dakota | 9.6 pCi/L |
| 3 |  Pennsylvania | 8.6 pCi/L |
| 4 |  Ohio | 7.8 pCi/L |
| 5 |  Washington | 7.5 pCi/L |
| 6 |  Kentucky | 7.4 pCi/L |
| 6 |  Montana | 7.4 pCi/L |
| 8 |  Idaho | 7.3 pCi/L |
| 9 |  Colorado | 6.8 pCi/L |
| 10 |  Iowa | 6.1 pCi/L |
| 10 |  West Virginia | 6.1 pCi/L |
| 12 |  North Dakota | 6.0 pCi/L |
| 13 |  Maine | 5.9 pCi/L |
| 14 |  Wisconsin | 5.7 pCi/L |
| 15 |  New Hampshire | 5.6 pCi/L |
| 16 |  Maryland | 5.4 pCi/L |
| 17 |  Illinois | 5.3 pCi/L |
| 18 |  Nebraska | 5.2 pCi/L |
| 19 |  Wyoming | 5.0 pCi/L |
| 20 |  Kansas | 4.9 pCi/L |
| 21 |  Tennessee | 4.8 pCi/L |
| 22 |  Indiana | 4.7 pCi/L |
| 23 |  Minnesota | 4.6 pCi/L |
| 24 |  New Jersey | 4.4 pCi/L |
| 24 |  Utah | 4.4 pCi/L |
| 26 |  Missouri | 4.3 pCi/L |
| 26 |  Rhode Island | 4.3 pCi/L |
| 28 |  New York | 4.2 pCi/L |
| 29 |  North Carolina | 4.0 pCi/L |
| 30 |  Massachusetts | 3.9 pCi/L |
| 30 |  Alabama | 3.9 pCi/L |
| 30 |  New Mexico | 3.9 pCi/L |
| 33 |  Vermont | 3.7 pCi/L |
| 34 |  Virginia | 3.6 pCi/L |
| 35 |  Michigan | 3.5 pCi/L |
| 36 |  Connecticut | 3.4 pCi/L |
| 36 |  Nevada | 3.4 pCi/L |
| 38 |  Oregon | 3.1 pCi/L |
| 39 |  Oklahoma | 2.5 pCi/L |
| 39 |  Arkansas | 2.5 pCi/L |
| 41 |  South Carolina | 2.4 pCi/L |
| 41 |  Delaware | 2.4 pCi/L |
| 43 |  California | 2.3 pCi/L |
| 43 |  Georgia | 2.3 pCi/L |
| 45 |  Texas | 2.1 pCi/L |
| 46 |  Arizona | 1.9 pCi/L |
| 47 |  Florida | 1.8 pCi/L |
| 48 |  District of Columbia | 1.6 pCi/L |
| 49 |  Mississippi | 1.2 pCi/L |
| 50 |  Louisiana | 1.1 pCi/L |
What correlates with Average Radon Level?
Pearson r against 2,087 other state metrics sharing at least 30 states. Correlation is not causation.
Higher together
Places that have a higher Average Radon Level tend to score higher on these
- Plot
- Plot
- Most & Least Intelligent States Index (Guru99)Dumbest States in the United StatesPlotr = +0.61 · strong · n = 30
- Plot
- Plot
- Average Days with Accumulated Snow 1 or More Inches Deep 1980-2010Snowiest StatesPlotr = +0.55 · strong · n = 48
Opposite directions
Places that have a higher Average Radon Level tend to score lower on these
Quick answers
- Which state has the highest Average Radon Level?
- Alaska has the highest Average Radon Level, at 10.7 pCi/L, followed by South Dakota (9.6 pCi/L) and Pennsylvania (8.6 pCi/L).
- Which state has the lowest Average Radon Level?
- Louisiana has the lowest Average Radon Level, at 1.1 pCi/L.
- What is the median Average Radon Level across US states?
- The median is 4.4 pCi/L across the 50 US states with data.
- Where does this radon levels by state data come from?
- Rankodex compiles it from World Population Review and the primary sources it cites: Interactive Radon Map - Radon; Radon Information and Resources by State - Radon; EPA Map of Radon Zones and Supplemental Information - United States Environmental Protection Agency; Radon - EPA.