EPA data as of Oct 2026 · page updated 2026-10-30
Idaho: drinking water & radon
Idaho has 774 active community water systems. Since 2016, 258 reported health-based violations; 2 had a latest lead result above 15 ppb; 3 measured PFOA or PFOS at or above 4 ppt.
Water systems774
With violations258
Radon zone 1 ZIPs137
ZIPs likely on wells186
Radon zones in Idaho
tap a countyZone 1 · highestZone 2 · moderateZone 3 · low
Most health-based violations
| Mission Creek Water ASSN 263 people | 84 |
| Clearwater Water Dist 80 people | 42 |
| Meadow Lark Court LLC 45 people | 41 |
| ELK City Water and Sewer ASSN 320 people | 40 |
| Cedar Springs Community Water 130 people | 27 |
| Bia North Idaho 490 people | 24 |
| Drake Subd 150 people | 24 |
| City of Bellevue 2,747 people | 22 |
| City of Juliaetta 624 people | 21 |
| Filer Water Works 2,858 people | 19 |
Highest latest lead (90th percentile)
| Parkwood 65 people | 104.6 ppb |
| New Hope Subd 100 people | 48.2 ppb |
| Pineview Estates Water Dist 450 people | 15 ppb |
| City of Arimo 368 people | 14 ppb |
| City of Dover 865 people | 14 ppb |
| Country Club Subdivisions Water ASSN 120 people | 14 ppb |
| Mountain View Estates 43 people | 13 ppb |
| Shotgun Cherokee Subd 5 245 people | 13 ppb |
| Highway Estates Water ASSN 65 people | 13 ppb |
| Helena Rv and Mobile Home Park 250 people | 12 ppb |
Highest PFOA / PFOS
| Garden City Water and Sewer System 12,500 people | 28.2 ppt |
| Capitol Water Corp 9,000 people | 9.8 ppt |
| Meridian Water Dept 152,070 people | 4.9 ppt |
Largest systems
| Veolia Water Idaho 264,978 people | 264,978 |
| Meridian Water Dept 152,070 people | 152,070 |
| City of Nampa 100,200 people | 100,200 |
| City of Caldwell 78,740 people | 78,740 |
| City of Idaho Falls 69,450 people | 69,450 |
| City of Pocatello 58,231 people | 58,231 |
| City of Twin Falls 56,121 people | 56,121 |
| City of Coeur D Alene 54,115 people | 54,115 |
| City of Rexburg 40,695 people | 40,695 |
| City of Kuna 32,038 people | 32,038 |
All ZIP codes in Idaho
312 ZIP codes.
83201Pocatello83202Pocatello83203Fort Hall83204Pocatello83205Pocatello83206Pocatello83209Pocatello83210Aberdeen83211American Falls83212Arbon83213Arco83214Arimo83217Bancroft83218Basalt83220Bern83221Blackfoot83223Bloomington83226Challis83227Clayton83228Clifton83229Cobalt83232Dayton83233Dingle83234Downey83235Ellis83236Firth83237Franklin83238Geneva83239Georgetown83241Grace83243Holbrook83244Howe83245Inkom83246Lava Hot Springs83250McCammon83251Mackay83252Malad City83253May83254Montpelier83255Moore83261Paris83262Pingree83263Preston83271Rockland83272Saint Charles83274Shelley83276Soda Springs83277Springfield83278Stanley83281Swanlake83283Thatcher83285Wayan83286Weston83287Fish Haven83301Twin Falls83302Rogerson83303Twin Falls83311Albion83312Almo83313Bellevue83314Bliss83316Buhl83318Burley83320Carey83321Castleford83322Corral83323Declo83324Dietrich83325Eden83327Fairfield83328Filer83330Gooding83332Hagerman83333Hailey83334Hansen83335Hazelton83336Heyburn83337Hill City83338Jerome83340Ketchum83341Kimberly83342Malta83343Minidoka83344Murtaugh83346Oakley83347Paul83348Picabo83349Richfield83350Rupert83352Shoshone83353Sun Valley83354Sun Valley83355Wendell83401Idaho Falls83402Idaho Falls83403Idaho Falls83404Idaho Falls83405Idaho Falls83406Idaho Falls83415Idaho Falls83420Ashton83421Chester83422Driggs83423Dubois83424Felt83425Hamer83427Iona83428Irwin83429Island Park83431Lewisville83433Macks Inn83434Menan83435Monteview83436Newdale83438Parker83440Rexburg83441Rexburg83442Rigby83443Ririe83444Roberts83445Saint Anthony83446Spencer83448Sugar City83449Swan Valley83450Terreton83451Teton83452Tetonia83455Victor83460Rexburg83462Carmen83463Gibbonsville83464Leadore83465Lemhi83466North Fork83467Salmon83468Tendoy83469Shoup83501Lewiston83520Ahsahka83522Cottonwood83523Craigmont83524Culdesac83525Elk City83526Ferdinand83530Grangeville83531Fenn83533Greencreek83535Juliaetta83536Kamiah83537Kendrick83539Kooskia83540Lapwai83541Lenore83542Lucile83543Nezperce83544Orofino83545Peck83546Pierce83547Pollock83548Reubens83549Riggins83552Stites83553Weippe83554White Bird83555Winchester83602Banks83604Bruneau83605Caldwell83606Caldwell83607Caldwell83610Cambridge83611Cascade83612Council83615Donnelly83616Eagle83617Emmett83619Fruitland83622Garden Valley83623Glenns Ferry83624Grand View83626Greenleaf83627Hammett83628Homedale83629Horseshoe Bend83630Huston83631Idaho City83632Indian Valley83633King Hill83634Kuna83635Lake Fork83636Letha83637Lowman83638McCall83639Marsing83641Melba83642Meridian83643Mesa83644Middleton83645Midvale83646Meridian83647Mountain Home83648Mountain Home Afb83650Murphy83651Nampa83652Nampa83653Nampa83654New Meadows83655New Plymouth83656Notus83657Ola83660Parma83661Payette83666Placerville83669Star83670Sweet83671Warren83672Weiser83676Wilder83677Yellow Pine83680Meridian83686Nampa83687Nampa83701Boise83702Boise83703Boise83704Boise83705Boise83706Boise83707Boise83708Boise83709Boise83711Boise83712Boise83713Boise83714Garden City83715Boise83716Boise83717Boise83719Boise83720Boise83722Boise83724Boise83726Boise83728Boise83729Boise83732Boise83735Boise83756Boise83799Boise83801Athol83802Avery83803Bayview83804Blanchard83805Bonners Ferry83806Bovill83808Calder83809Careywood83810Cataldo83811Clark Fork83812Clarkia83813Cocolalla83814Coeur d'Alene83815Coeur d'Alene83816Coeur d'Alene83821Coolin83822Oldtown83823Deary83824Desmet83825Dover83826Eastport83827Elk River83830Fernwood83832Genesee83833Harrison83834Harvard83835Hayden83836Hope83837Kellogg83839Kingston83840Kootenai83841Laclede83842Medimont83843Moscow83844Moscow83845Moyie Springs83846Mullan83847Naples83848Nordman83849Osburn83850Pinehurst83851Plummer83852Ponderay83854Post Falls83855Potlatch83856Priest River83857Princeton83858Rathdrum83860Sagle83861Saint Maries83864Sandpoint83865Colburn83866Santa83867Silverton83868Smelterville83869Spirit Lake83870Tensed83871Troy83872Viola83873Wallace83874Murray83876Worley83877Post Falls
What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.
Questions
How many water systems in Idaho have violations?
258 of 774 active community water systems in Idaho reported at least one health-based violation since 2016 (EPA SDWIS).
What is the radon risk in Idaho?
137 ZIP codes are in EPA radon zone 1 (highest potential), 154 in zone 2 and 21 in zone 3. EPA recommends testing every home.