2026 Rankings

Highest Radon Risk ZIP Codes in Washington — 2026

Last updated: June 4, 2026

133 ZIP codes ranked by Radon Zone #1: ZIP 98601 (Amboy, WA) — Zone 1 (High)
Lead Violations Lowest Score Safest Flood Risk Energy Cost Radon PFAS Reliability EJ Index Homebuyer Risk CO & Gas Safest Gas Remediation Burden Unresolved Violations (by Utility) Water Equity (by Utility)

Out of 133 ZIP codes with data in Washington, these are the lowest-ranked areas for radon zone. See also: National ZIP Codes with Highest Radon Risk | All Washington Rankings

Statistic Value
ZIP codes ranked 133
Lowest value Zone 1 (High)
Median value Zone 1 (High)
State Washington

100 Lowest-Ranked ZIP Codes

Rank ZIP Code City State Radon Zone Safety Score
1 98601 Amboy WA Zone 1 (High) 40/100
2 98603 Ariel WA Zone 1 (High) 40/100
3 98616 Cougar WA Zone 1 (High) 40/100
4 98819 Conconully WA Zone 1 (High) 40/100
5 98827 Loomis WA Zone 1 (High) 40/100
6 98859 Wauconda WA Zone 1 (High) 40/100
7 99001 Airway Heights WA Zone 1 (High) 40/100
8 99011 Fairchild Air Force Base WA Zone 1 (High) 40/100
9 99013 Ford WA Zone 1 (High) 40/100
10 99023 Mica WA Zone 1 (High) 40/100
11 99034 Tumtum WA Zone 1 (High) 40/100
12 99040 Wellpinit WA Zone 1 (High) 40/100
13 99101 Addy WA Zone 1 (High) 40/100
14 99107 Boyds WA Zone 1 (High) 40/100
15 99110 Clayton WA Zone 1 (High) 40/100
16 99126 Evans WA Zone 1 (High) 40/100
17 99129 Fruitland WA Zone 1 (High) 40/100
18 99131 Gifford WA Zone 1 (High) 40/100
19 99138 Inchelium WA Zone 1 (High) 40/100
20 99140 Keller WA Zone 1 (High) 40/100
21 99146 Laurier WA Zone 1 (High) 40/100
22 99151 Marcus WA Zone 1 (High) 40/100
23 99153 Metaline Falls WA Zone 1 (High) 40/100
24 99160 Orient WA Zone 1 (High) 40/100
25 99181 Valley WA Zone 1 (High) 40/100
26 98648 Stevenson WA Zone 1 (High) 42/100
27 98852 Stehekin WA Zone 1 (High) 45/100
28 99118 Curlew WA Zone 1 (High) 48/100
29 99156 Newport WA Zone 1 (High) 51/100
30 98606 Brush Prairie WA Zone 1 (High) 53/100
31 98622 Heisson WA Zone 1 (High) 53/100
32 98629 La Center WA Zone 1 (High) 53/100
33 98814 Carlton WA Zone 1 (High) 53/100
34 98833 Mazama WA Zone 1 (High) 53/100
35 99026 Nine Mile Falls WA Zone 1 (High) 53/100
36 99027 Otis Orchards WA Zone 1 (High) 53/100
37 99036 Valleyford WA Zone 1 (High) 53/100
38 99037 Veradale WA Zone 1 (High) 53/100
39 99121 Danville WA Zone 1 (High) 53/100
40 99137 Hunters WA Zone 1 (High) 53/100
41 99150 Malo WA Zone 1 (High) 53/100
42 99167 Rice WA Zone 1 (High) 53/100
43 99020 Marshall WA Zone 1 (High) 54/100
44 99114 Colville WA Zone 1 (High) 56/100
45 98849 Riverside WA Zone 1 (High) 59/100
46 99119 Cusick WA Zone 1 (High) 60/100
47 98610 Carson WA Zone 1 (High) 61/100
48 99004 Cheney WA Zone 1 (High) 61/100
49 99166 Republic WA Zone 1 (High) 61/100
50 99180 Usk WA Zone 1 (High) 61/100
51 99021 Mead WA Zone 1 (High) 62/100
52 98607 Camas WA Zone 1 (High) 63/100
53 98840 Okanogan WA Zone 1 (High) 63/100
54 99009 Elk WA Zone 1 (High) 63/100
55 98604 Battle Ground WA Zone 1 (High) 64/100
56 98862 Winthrop WA Zone 1 (High) 64/100
57 99039 Waverly WA Zone 1 (High) 64/100
58 99155 Nespelem WA Zone 1 (High) 64/100
59 99157 Northport WA Zone 1 (High) 64/100
60 98605 Bingen WA Zone 1 (High) 65/100
61 98668 Vancouver WA Zone 1 (High) 65/100
62 98671 Washougal WA Zone 1 (High) 65/100
63 98687 Vancouver WA Zone 1 (High) 65/100
64 98844 Oroville WA Zone 1 (High) 65/100
65 99173 Springdale WA Zone 1 (High) 65/100
66 98829 Malott WA Zone 1 (High) 66/100
67 99006 Deer Park WA Zone 1 (High) 66/100
68 99014 Four Lakes WA Zone 1 (High) 66/100
69 99016 Greenacres WA Zone 1 (High) 66/100
70 99116 Coulee Dam WA Zone 1 (High) 66/100
71 99124 Elmer City WA Zone 1 (High) 66/100
72 99205 Spokane WA Zone 1 (High) 66/100
73 99209 Spokane WA Zone 1 (High) 66/100
74 99211 Spokane WA Zone 1 (High) 66/100
75 99213 Spokane WA Zone 1 (High) 66/100
76 99214 Spokane WA Zone 1 (High) 66/100
77 99215 Spokane WA Zone 1 (High) 66/100
78 99216 Spokane WA Zone 1 (High) 66/100
79 99219 Spokane WA Zone 1 (High) 66/100
80 99220 Spokane WA Zone 1 (High) 66/100
81 99228 Spokane WA Zone 1 (High) 66/100
82 99251 Spokane WA Zone 1 (High) 66/100
83 99252 Spokane WA Zone 1 (High) 66/100
84 99256 Spokane WA Zone 1 (High) 66/100
85 99258 Spokane WA Zone 1 (High) 66/100
86 99260 Spokane WA Zone 1 (High) 66/100
87 99299 Spokane WA Zone 1 (High) 66/100
88 98675 Yacolt WA Zone 1 (High) 67/100
89 98846 Pateros WA Zone 1 (High) 67/100
90 99031 Spangle WA Zone 1 (High) 67/100
91 99148 Loon Lake WA Zone 1 (High) 67/100
92 99109 Chewelah WA Zone 1 (High) 68/100
93 99152 Metaline WA Zone 1 (High) 68/100
94 98660 Vancouver WA Zone 1 (High) 69/100
95 98661 Vancouver WA Zone 1 (High) 69/100
96 98662 Vancouver WA Zone 1 (High) 69/100
97 98663 Vancouver WA Zone 1 (High) 69/100
98 98664 Vancouver WA Zone 1 (High) 69/100
99 98665 Vancouver WA Zone 1 (High) 69/100
100 98666 Vancouver WA Zone 1 (High) 69/100

Methodology

Radon rankings are based on EPA county-level radon zone classifications. Zone 1 (highest risk) has predicted average indoor radon levels above 4 pCi/L — the EPA action level. Zone 2 is moderate (2-4 pCi/L) and Zone 3 is low (below 2 pCi/L). Within Zone 1, ZIP codes are sub-ranked by Home Safety Score to prioritize areas with compounding risk factors.

Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-06-04.

Frequently Asked Questions

What is EPA Radon Zone 1?

Zone 1 is the EPA highest-risk classification, meaning the county has predicted average indoor radon levels above 4 pCi/L — the level at which the EPA recommends mitigation. Radon causes about 21,000 lung cancer deaths per year in the U.S.

Should I test for radon?

The EPA recommends testing all homes regardless of radon zone. A DIY test kit costs $15-40. Professional testing costs $150-250. If levels exceed 4 pCi/L, mitigation systems ($800-2,500) can reduce radon by up to 99%.

Explore More Rankings

How this ranking is calculated, data sources, and limitations: Rankings Methodology →

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Disclaimer: Rankings are based on EPA, FEMA, and federal agency data. They reflect historical patterns and risk indicators, not necessarily current conditions. For the most current information, contact your local water utility or request a Consumer Confidence Report.

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