Results from entry points (water leaving treatment, not household taps) of public water systems sampled under EPA's Fifth Unregulated Contaminant Monitoring Rule. Click a county to see every water system serving it, or turn on service areas and click a location to see the systems that serve that spot.
206 of the 1,936 public water systems listed for Wisconsin were sampled. Sorted by the highest single result relative to EPA's 2024 limits. Each name links to a page with all of that system's results. All 1,936 Wisconsin systems, including those not tested · Download all Wisconsin results (CSV, gzip)
| System | PWSID | City | Population | PFOA (ppt) | PFOS (ppt) | HI | Highest single result |
|---|---|---|---|---|---|---|---|
| Prairie Du Chien Waterworks | WI6120250 | Prairie Du Chien | 6,005 | <MRL | 39 | 1.1 | PFOS ≥ 3 × its limit |
| Saukville Waterworks | WI2460134 | Saukville | 4,268 | 4.2 | 31 | 7.314 | PFOS ≥ 3 × its limit |
| Pewaukee City Water And Sewer Utility | WI2680214 | Pewaukee | 8,671 | 8.5 | 12 | 6.913 | Hazard Index ≥ 3 × its limit |
| Tomahawk Waterworks | WI7350127 | Tomahawk | 3,180 | 21 | <MRL | 0 | PFOA ≥ 3 × its limit |
| Kewaskum Waterworks | WI2670112 | Kewaskum | 4,309 | 15 | <MRL | 0.003 | PFOA ≥ 3 × its limit |
| Marshfield Utilities | WI7720165 | Marshfield | 18,815 | <MRL | 14 | 1.402 | PFOS ≥ 3 × its limit |
| Weston Municipal Utilities | WI7370163 | Weston | 16,000 | 5.9 | 13 | 0.585 | PFOS ≥ 3 × its limit |
| Prescott Waterworks | WI6480243 | Prescott | 4,258 | 9.9 | <MRL | 1.802 | PFOA 1–3 × its limit |
| Rib Mountain Water Utility | WI7370660 | Wausau | 6,398 | 5.2 | 9.4 | 0.922 | PFOS 1–3 × its limit |
| Concor Tool And Machine Inc | WI8581084 | Hayward | 57 | 8.5 | 6.7 | 0.003 | PFOA 1–3 × its limit |
| Hartford Waterworks | WI2670110 | Hartford | 15,805 | 6.8 | 5.5 | 0.61 | PFOA 1–3 × its limit |
| Rhinelander Water & Wastewater | WI7440126 | Rhinelander | 8,234 | 6.8 | <MRL | 0 | PFOA 1–3 × its limit |
| West Bend Waterworks | WI2670120 | West Bend | 32,149 | 6.5 | <MRL | 0.002 | PFOA 1–3 × its limit |
| Palmyra Waterworks | WI1280112 | Palmyra | 1,756 | <MRL | 6.2 | 0.32 | PFOS 1–3 × its limit |
| La Crosse Waterworks | WI6320309 | La Crosse | 53,000 | 5.1 | 5.5 | 0.84 | PFOS 1–3 × its limit |
| Sturgeon Bay Waterworks | WI4150526 | Sturgeon Bay | 9,700 | <MRL | 4.2 | 1.3 | Hazard Index 1–3 × its limit |
| Sheboygan Tn Waterworks | WI4600403 | Sheboygan | 4,596 | <MRL | <MRL | 1.202 | Hazard Index 1–3 × its limit |
| Lake Geneva Utility Commission | WI2650066 | Lake Geneva | 7,107 | 4.7 | <MRL | 0.393 | PFOA 1–3 × its limit |
| Schofield Waterworks | WI7370162 | Schofield | 2,205 | 4.7 | <MRL | 0.625 | PFOA 1–3 × its limit |
| Hartland Waterworks | WI2680205 | Hartland | 9,212 | 4.4 | 4.6 | 0.362 | PFOS 1–3 × its limit |
| Eau Claire Waterworks | WI6180230 | Eau Claire | 70,587 | <MRL | <MRL | 1.1 | Hazard Index 1–3 × its limit |
| Waupaca Waterworks | WI4690402 | Waupaca | 6,062 | <MRL | 4.3 | 0.004 | PFOS 1–3 × its limit |
| Medford Waterworks | WI8610125 | Medford | 4,318 | 4.1 | <MRL | 0.52 | PFOA 1–3 × its limit |
| Portage Waterworks | WI1110039 | Portage | 10,437 | <MRL | <MRL | 0.81 | Hazard Index below its limit |
| Madison Water Utility | WI1130224 | Madison | 272,000 | <MRL | <MRL | 0.73 | Hazard Index below its limit |
| Slinger Water Utility | WI2670116 | Slinger | 5,659 | <MRL | <MRL | 0.57 | Hazard Index below its limit |
| Tomah Waterworks | WI6420254 | Tomah | 9,192 | <MRL | <MRL | 0.57 | Hazard Index below its limit |
| Monona Waterworks | WI1130245 | Monona | 8,624 | <MRL | <MRL | 0.542 | Hazard Index below its limit |
| Reedsburg Waterworks | WI1570102 | Reedsburg | 9,984 | <MRL | <MRL | 0.44 | Hazard Index below its limit |
| Mcfarland Waterworks | WI1130241 | Mcfarland | 9,676 | <MRL | <MRL | 0.37 | Hazard Index below its limit |
| Stoughton Waterworks | WI1130078 | Stoughton | 13,078 | <MRL | <MRL | 0.36 | Hazard Index below its limit |
| Mt Horeb Waterworks | WI1130247 | Mount Horeb | 7,756 | <MRL | <MRL | 0.33 | Hazard Index below its limit |
| Brookfield Water Utility | WI2680253 | Brookfield | 29,070 | <MRL | <MRL | 0.322 | Hazard Index below its limit |
| Lac Du Flambeau | 055295401 | Lac Du Flambeau | 2,962 | <MRL | <MRL | 0.004 | Hazard Index below its limit |
| Town Of Brookfield San Dist 4 | WI2680239 | Brookfield | 6,419 | <MRL | <MRL | 0.004 | Hazard Index below its limit |
| Beloit City Of | WI1540112 | Beloit | 36,677 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Chippewa Falls Waterworks | WI6090456 | Chippewa Falls | 13,375 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| East Troy Waterworks | WI2650123 | East Troy | 5,054 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Oconomowoc Waterworks | WI2680227 | Oconomowoc | 15,805 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Onalaska Waterworks | WI6320327 | Onalaska | 18,000 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Verona Waterworks | WI1130259 | Verona | 14,030 | <MRL | <MRL | 0.002 | Hazard Index below its limit |
| Appleton Waterworks | WI4450333 | Appleton | 74,511 | <MRL | <MRL | 0 | Other PFAS detected |
| Black River Falls Waterworks | WI6270244 | Black River Falls | 3,608 | <MRL | <MRL | 0 | Other PFAS detected |
| Ellsworth Waterworks | WI6480239 | Ellsworth | 3,304 | <MRL | <MRL | 0 | Other PFAS detected |
| Harrison Utilities-Fka Waverly Sd | WI4080076 | Menasha | 5,500 | <MRL | <MRL | 0 | Other PFAS detected |
| Holmen Waterworks | WI6320306 | Holmen | 10,147 | <MRL | <MRL | 0 | Other PFAS detected |
| Hudson Waterworks | WI6560087 | Hudson | 18,558 | <MRL | <MRL | 0 | Other PFAS detected |
| New London Waterworks | WI4690398 | New London | 7,187 | <MRL | <MRL | 0 | Other PFAS detected |
| New Richmond Waterworks | WI6560126 | New Richmond | 10,824 | <MRL | <MRL | 0 | Other PFAS detected |
| Pewaukee Village Waterworks | WI2680229 | Pewaukee | 8,166 | <MRL | <MRL | 0 | Other PFAS detected |
| Plover Waterworks | WI7500726 | Plover | 13,486 | <MRL | <MRL | 0 | Other PFAS detected |
| Shawano Lk San Dist 1 | WI4590457 | Shawano | 4,950 | <MRL | <MRL | 0 | Other PFAS detected |
| Wausau Waterworks | WI7370102 | Wausau | 39,994 | <MRL | <MRL | 0 | Other PFAS detected |
| Allouez Waterworks | WI4050455 | Green Bay | 13,923 | <MRL | <MRL | 0 | No PFAS detected |
| Altoona Waterworks | WI6180280 | Altoona | 9,627 | <MRL | <MRL | 0 | No PFAS detected |
| Antigo Waterworks | WI7340086 | Antigo | 7,780 | <MRL | <MRL | 0 | No PFAS detected |
| Arena Waterworks | WI1250073 | Arena | 877 | <MRL | <MRL | 0 | No PFAS detected |
| Ashland Water Utility | WI8020373 | Ashland | 8,000 | <MRL | <MRL | 0 | No PFAS detected |
| Ashwaubenon Waterworks | WI4050456 | Ashwaubenon | 17,730 | <MRL | <MRL | 0 | No PFAS detected |
| Baldwin Waterworks | WI6560119 | Baldwin | 4,440 | <MRL | <MRL | 0 | No PFAS detected |
| Baraboo Waterworks | WI1570085 | Baraboo | 12,703 | <MRL | <MRL | 0 | No PFAS detected |
| Barron Light & Water Dept | WI6030125 | Barron | 3,423 | <MRL | <MRL | 0 | No PFAS detected |
| Beaver Dam Water Utility | WI1140059 | Beaver Dam | 16,200 | <MRL | <MRL | 0 | No PFAS detected |
| Bellevue Waterworks | WI4050459 | Green Bay | 16,715 | <MRL | <MRL | 0 | No PFAS detected |
| Berlin Waterworks | WI4240216 | Berlin | 5,524 | <MRL | <MRL | 0 | No PFAS detected |
| Birds Eye Foods | WI2650399 | Darien | 610 | <MRL | <MRL | 0 | No PFAS detected |
| Bloomer Waterworks | WI6090448 | Bloomer | 3,680 | <MRL | <MRL | 0 | No PFAS detected |
| Bloomfield, Village Of | WI2651469 | Pell Lake | 4,071 | <MRL | <MRL | 0 | No PFAS detected |
| Bloomington Waterworks | WI1220085 | Bloomington | 682 | <MRL | <MRL | 0 | No PFAS detected |
| Brillion Waterworks | WI4080221 | Brillion | 3,262 | <MRL | <MRL | 0 | No PFAS detected |
| Brown Deer Waterworks | WI2410556 | Brown Deer | 12,741 | <MRL | <MRL | 0 | No PFAS detected |
| Burlington Waterworks | WI2520177 | Burlington | 11,043 | <MRL | <MRL | 0 | No PFAS detected |
| Cabelas - Richfield | WI2671753 | Richfield | 3,931 | <MRL | <MRL | 0 | No PFAS detected |
| Caledonia Water Utility - Village Of | WI2520184 | Caledonia | 21,819 | <MRL | <MRL | 0 | No PFAS detected |
| Cedarburg L & W Commission | WI2460108 | Cedarburg | 12,500 | <MRL | <MRL | 0 | No PFAS detected |
| Chilton Waterworks | WI4080222 | Chilton | 4,191 | <MRL | <MRL | 0 | No PFAS detected |
| Clinton Waterworks | WI1540114 | Clinton | 2,119 | <MRL | <MRL | 0 | No PFAS detected |
| Clintonville Utilities | WI4690391 | Clintonville | 4,635 | <MRL | <MRL | 0 | No PFAS detected |
| Columbus Utilities | WI1110038 | Columbus | 5,173 | <MRL | <MRL | 0 | No PFAS detected |
| Combined Locks Waterworks | WI4450409 | Combined Locks | 3,609 | <MRL | <MRL | 0 | No PFAS detected |
| Cottage Grove Waterworks | WI1130218 | Cottage Grove | 9,345 | <MRL | <MRL | 0 | No PFAS detected |
| Cross Plains Waterworks | WI1130219 | Cross Plains | 4,100 | <MRL | <MRL | 0 | No PFAS detected |
| Cudahy Waterworks | WI2410169 | Cudahy | 18,659 | <MRL | <MRL | 0 | No PFAS detected |
| Darboy Sanitary Dist 1 | WI4450117 | Appleton | 13,024 | <MRL | <MRL | 0 | No PFAS detected |
| De Pere Waterworks Sa 1 | WI4050453 | De Pere | 25,660 | <MRL | <MRL | 0 | No PFAS detected |
| Deforest Waterworks | WI1130221 | Deforest | 10,500 | <MRL | <MRL | 0 | No PFAS detected |
| Delavan Waterworks | WI2650113 | Delavan | 9,028 | <MRL | <MRL | 0 | No PFAS detected |
| Denmark Waterworks | WI4050351 | Denmark | 2,684 | <MRL | <MRL | 0 | No PFAS detected |
| Dodgeville Waterworks | WI1250079 | Dodgeville | 4,583 | <MRL | <MRL | 0 | No PFAS detected |
| Eau Galle Cheese Factory Llc | WI6470186 | Durand | 50 | <MRL | <MRL | 0 | No PFAS detected |
| Edgerton Waterworks | WI1540119 | Edgerton | 5,512 | <MRL | <MRL | 0 | No PFAS detected |
| Elkhorn Waterworks | WI2650062 | Elkhorn | 10,317 | <MRL | <MRL | 0 | No PFAS detected |
| Evansville Waterworks | WI1540047 | Evansville | 5,703 | <MRL | <MRL | 0 | No PFAS detected |
| Fitchburg Utility Dist 1 | WI1130231 | Fitchburg | 29,900 | <MRL | <MRL | 0 | No PFAS detected |
| Fond Du Lac Waterworks | WI4200469 | Fond Du Lac | 44,678 | <MRL | <MRL | 0 | No PFAS detected |
| Forest Junction Pub Util | WI4080377 | Forest Junction | 487 | <MRL | <MRL | 0 | No PFAS detected |
| Fort Atkinson Waterworks | WI1280103 | Fort Atkinson | 12,390 | <MRL | <MRL | 0 | No PFAS detected |
| Fort Mccoy North Post | WI6420302 | Fort Mccoy | 10,000 | <MRL | <MRL | 0 | No PFAS detected |
| Fox Crossing Utilities East | WI4710453 | Neenah | 10,927 | <MRL | <MRL | 0 | No PFAS detected |
| Fox Crossing Utilities West | WI4710358 | Neenah | 14,000 | <MRL | <MRL | 0 | No PFAS detected |
| Fox Point Waterworks | WI2410584 | Fox Point | 6,808 | <MRL | <MRL | 0 | No PFAS detected |
| Franklin Water Utility | WI2410563 | Franklin | 22,500 | <MRL | <MRL | 0 | No PFAS detected |
| Germantown Water Utility | WI2670105 | Germantown | 20,027 | <MRL | <MRL | 0 | No PFAS detected |
| Glendale Waterworks | WI2410168 | Glendale | 12,883 | <MRL | <MRL | 0 | No PFAS detected |
| Grafton Waterworks | WI2460111 | Grafton | 12,269 | <MRL | <MRL | 0 | No PFAS detected |
| Grand Chute Tn San Dist 1 | WI4450429 | Grand Chute | 21,583 | <MRL | <MRL | 0 | No PFAS detected |
| Green Bay Waterworks | WI4050356 | Green Bay | 107,369 | <MRL | <MRL | 0 | No PFAS detected |
| Greendale Waterworks | WI2410571 | Greendale | 14,393 | <MRL | <MRL | 0 | No PFAS detected |
| Greenville Utilities Vil Of | WI4450278 | Greenville | 11,340 | <MRL | <MRL | 0 | No PFAS detected |
| Hilbert Waterworks | WI4080269 | Hilbert | 1,176 | <MRL | <MRL | 0 | No PFAS detected |
| Ho Chunk Casino | WI1570639 | Black River Falls | 5,486 | <MRL | <MRL | 0 | No PFAS detected |
| Horicon Waterworks | WI1140146 | Horicon | 3,682 | <MRL | <MRL | 0 | No PFAS detected |
| Howard Waterworks | WI4050468 | Green Bay | 21,133 | <MRL | <MRL | 0 | No PFAS detected |
| Jackson Waterworks | WI2670111 | Jackson | 8,397 | <MRL | <MRL | 0 | No PFAS detected |
| Janesville Water Utility | WI1540127 | Janesville | 64,415 | <MRL | <MRL | 0 | No PFAS detected |
| Jefferson Waterworks | WI1280104 | Jefferson | 7,926 | <MRL | <MRL | 0 | No PFAS detected |
| Kaukauna Utilities | WI4450336 | Kaukauna | 17,493 | <MRL | <MRL | 0 | No PFAS detected |
| Kenosha Water Utility | WI2300046 | Kenosha | 99,218 | <MRL | <MRL | 0 | No PFAS detected |
| Keshena | 055295508 | Keshena | 3,960 | <MRL | <MRL | 0 | No PFAS detected |
| Kiel Waterworks | WI4360427 | Kiel | 3,932 | <MRL | <MRL | 0 | No PFAS detected |
| Kimberly Waterworks | WI4450342 | Kimberly | 7,608 | <MRL | <MRL | 0 | No PFAS detected |
| Kronenwetter Water & Sewer Utility | WI7371700 | Kronenwetter | 6,931 | <MRL | <MRL | 0 | No PFAS detected |
| Lake Hallie Waterworks Village Of | WI6090849 | Chippewa Falls | 6,701 | <MRL | <MRL | 0 | No PFAS detected |
| Lake Mills Waterworks | WI1280108 | Lake Mills | 6,211 | <MRL | <MRL | 0 | No PFAS detected |
| Lancaster Waterworks | WI1220107 | Lancaster | 3,907 | <MRL | <MRL | 0 | No PFAS detected |
| Lawrence Waterworks | WI4051625 | De Pere | 5,398 | <MRL | <MRL | 0 | No PFAS detected |
| Ledgeview Tn Sanitary Dist 2 | WI4051418 | De Pere | 7,602 | <MRL | <MRL | 0 | No PFAS detected |
| Little Chute Waterworks | WI4450338 | Little Chute | 12,168 | <MRL | <MRL | 0 | No PFAS detected |
| Manitowoc Waterworks | WI4360364 | Manitowoc | 34,500 | <MRL | <MRL | 0 | No PFAS detected |
| Marinette Waterworks | WI4380395 | Marinette | 10,968 | <MRL | <MRL | 0 | No PFAS detected |
| Marshall Waterworks | WI1130237 | Marshall | 3,862 | <MRL | <MRL | 0 | No PFAS detected |
| Mauston Green Acres | WI7290134 | Colfax | 40 | <MRL | <MRL | 0 | No PFAS detected |
| Mauston Waterworks | WI7290129 | Mauston | 4,456 | <MRL | <MRL | 0 | No PFAS detected |
| Mayville Waterworks | WI1140057 | Mayville | 5,112 | <MRL | <MRL | 0 | No PFAS detected |
| Menasha Elec & Water Util | WI4710334 | Menasha | 15,144 | <MRL | <MRL | 0 | No PFAS detected |
| Menomonee Falls Ww - Surface Water | WI2680082 | Menomonee Falls | 23,867 | <MRL | <MRL | 0 | No PFAS detected |
| Menomonie Waterworks | WI6170268 | Menomonie | 15,950 | <MRL | <MRL | 0 | No PFAS detected |
| Mequon Water Utility | WI2460112 | Mequon | 11,152 | <MRL | <MRL | 0 | No PFAS detected |
| Merrill Waterworks | WI7350123 | Merrill | 9,661 | <MRL | <MRL | 0 | No PFAS detected |
| Middleton Waterworks | WI1130242 | Middleton | 23,868 | <MRL | <MRL | 0 | No PFAS detected |
| Milton Waterworks | WI1540130 | Milton | 5,588 | <MRL | <MRL | 0 | No PFAS detected |
| Milwaukee Waterworks | WI2410100 | Milwaukee | 626,000 | <MRL | <MRL | 0 | No PFAS detected |
| Monroe Waterworks | WI1230078 | Monroe | 10,780 | <MRL | <MRL | 0 | No PFAS detected |
| Mt Zion Christian Church | WI2650822 | Lake Geneva | 509 | <MRL | <MRL | 0 | No PFAS detected |
| Mukwonago Waterworks | WI2680209 | Mukwonago | 8,190 | <MRL | <MRL | 0 | No PFAS detected |
| Muskego Water Utility | WI2681741 | Muskego | 8,150 | <MRL | <MRL | 0 | No PFAS detected |
| Neenah Waterworks | WI4710348 | Neenah | 27,506 | <MRL | <MRL | 0 | No PFAS detected |
| New Berlin Water Utility | WI2680217 | New Berlin | 27,899 | <MRL | <MRL | 0 | No PFAS detected |
| New Berlin West Middle High School | WI2680813 | New Berlin | 1,380 | <MRL | <MRL | 0 | No PFAS detected |
| North Fond Du Lac Waterworks | WI4200405 | North Fond Du Lac | 5,414 | <MRL | <MRL | 0 | No PFAS detected |
| North Shore Water Commission | WI2413515 | Milwaukee | 35,598 | <MRL | <MRL | 0 | No PFAS detected |
| Oak Creek Waterworks | WI2410172 | Oak Creek | 32,104 | <MRL | <MRL | 0 | No PFAS detected |
| Oconto Waterworks | WI4430495 | Oconto | 4,583 | <MRL | <MRL | 0 | No PFAS detected |
| Omro Waterworks | WI4710357 | Omro | 3,629 | <MRL | <MRL | 0 | No PFAS detected |
| Oneida #1 Or Site #1 | 055295703 | Oneida | 4,393 | <MRL | <MRL | 0 | No PFAS detected |
| Oregon Waterworks | WI1130251 | Oregon | 11,200 | <MRL | <MRL | 0 | No PFAS detected |
| Oshkosh Waterworks | WI4710457 | Oshkosh | 63,000 | <MRL | <MRL | 0 | No PFAS detected |
| Peshtigo Waterworks | WI4380442 | Peshtigo | 3,420 | <MRL | <MRL | 0 | No PFAS detected |
| Pikes Bay Marina | WI8040687 | Bayfield | 45 | <MRL | <MRL | 0 | No PFAS detected |
| Platteville Waterworks | WI1220115 | Platteville | 12,268 | <MRL | <MRL | 0 | No PFAS detected |
| Pleasant Prairie Water Utility | WI2300167 | Pleasant Prairie | 10,754 | <MRL | <MRL | 0 | No PFAS detected |
| Plymouth Utilities | WI4600446 | Plymouth | 8,964 | <MRL | <MRL | 0 | No PFAS detected |
| Port Washington Waterworks | WI2460054 | Port Washington | 12,853 | <MRL | <MRL | 0 | No PFAS detected |
| Prairie Du Sac Waterworks | WI1570100 | Prairie Du Sac | 4,006 | <MRL | <MRL | 0 | No PFAS detected |
| Pulaski Waterworks | WI4050355 | Pulaski | 4,040 | <MRL | <MRL | 0 | No PFAS detected |
| Racine Waterworks | WI2520062 | Racine | 105,100 | <MRL | <MRL | 0 | No PFAS detected |
| Rice Lake Waterworks | WI6030138 | Rice Lake | 9,012 | <MRL | <MRL | 0 | No PFAS detected |
| Richland Center Waterworks | WI1530068 | Richland Center | 5,100 | <MRL | <MRL | 0 | No PFAS detected |
| Ripon Water Utility | WI4200476 | Ripon | 7,716 | <MRL | <MRL | 0 | No PFAS detected |
| River Falls Waterworks | WI6480246 | River Falls | 16,000 | <MRL | <MRL | 0 | No PFAS detected |
| Sauk City Waterworks | WI1570105 | Sauk City | 3,518 | <MRL | <MRL | 0 | No PFAS detected |
| Schreiber Foods Inc | WI2670302 | West Bend | 260 | <MRL | <MRL | 0 | No PFAS detected |
| Seymour Waterworks | WI4450337 | Seymour | 3,601 | <MRL | <MRL | 0 | No PFAS detected |
| Shawano Waterworks | WI4590456 | Shawano | 9,610 | <MRL | <MRL | 0 | No PFAS detected |
| Sheboygan Falls Utilities | WI4600455 | Sheboygan Falls | 8,687 | <MRL | <MRL | 0 | No PFAS detected |
| Sheboygan Water Utilities | WI4600354 | Sheboygan | 49,931 | <MRL | <MRL | 0 | No PFAS detected |
| Shorewood Waterworks | WI2410607 | Shorewood | 13,535 | <MRL | <MRL | 0 | No PFAS detected |
| Shullsburg Waterworks | WI1330076 | Shullsburg | 1,222 | <MRL | <MRL | 0 | No PFAS detected |
| Somers Water Utility | WI2301421 | Somers | 1,930 | <MRL | <MRL | 0 | No PFAS detected |
| South Milwaukee Waterworks | WI2410144 | South Milwaukee | 21,340 | <MRL | <MRL | 0 | No PFAS detected |
| South-Central Water System | 055295003 | Bowler | 2,805 | <MRL | <MRL | 0 | No PFAS detected |
| Sparta Waterworks | WI6420297 | Sparta | 10,025 | <MRL | <MRL | 0 | No PFAS detected |
| St Edward Sch & Ch | WI4450623 | Appleton | 505 | <MRL | <MRL | 0 | No PFAS detected |
| Stanley Waterworks | WI6090462 | Stanley | 3,500 | <MRL | <MRL | 0 | No PFAS detected |
| Stevens Point Waterworks | WI7500141 | Stevens Point | 26,717 | <MRL | <MRL | 0 | No PFAS detected |
| Suamico Waterworks | WI4051031 | Suamico | 4,697 | <MRL | <MRL | 0 | No PFAS detected |
| Sun Prairie Utilities | WI1130258 | Sun Prairie | 39,300 | <MRL | <MRL | 0 | No PFAS detected |
| Superior Water Light & Power Company | WI8160147 | Superior | 26,084 | <MRL | <MRL | 0 | No PFAS detected |
| Sussex Village Hall & Water Utility | WI2680233 | Sussex | 11,750 | <MRL | <MRL | 0 | No PFAS detected |
| Two Rivers Waterworks | WI4360436 | Two Rivers | 11,270 | <MRL | <MRL | 0 | No PFAS detected |
| Union Grove Waterworks | WI2520200 | Union Grove | 4,900 | <MRL | <MRL | 0 | No PFAS detected |
| Viroqua Waterworks | WI6630263 | Viroqua | 4,362 | <MRL | <MRL | 0 | No PFAS detected |
| Waterford Waterworks | WI2520202 | Waterford | 5,368 | <MRL | <MRL | 0 | No PFAS detected |
| Waterloo Waterworks | WI1280115 | Waterloo | 3,520 | <MRL | <MRL | 0 | No PFAS detected |
| Watertown Waterworks | WI1280044 | Watertown | 23,945 | <MRL | <MRL | 0 | No PFAS detected |
| Waukesha Water Utility | WI2680238 | Waukesha | 70,718 | <MRL | <MRL | 0 | No PFAS detected |
| Waunakee Waterworks | WI1130265 | Waunakee | 14,879 | <MRL | <MRL | 0 | No PFAS detected |
| Waupun Correctional Inst | WI1140142 | Madison | 3,706 | <MRL | <MRL | 0 | No PFAS detected |
| Waupun Utilities | WI1140131 | Waupun | 8,056 | <MRL | <MRL | 0 | No PFAS detected |
| Wauwatosa Waterworks | WI2410596 | Wauwatosa | 49,064 | <MRL | <MRL | 0 | No PFAS detected |
| West Allis Waterworks | WI2410595 | West Allis | 63,240 | <MRL | <MRL | 0 | No PFAS detected |
| West Salem Waterworks | WI6320334 | West Salem | 5,045 | <MRL | <MRL | 0 | No PFAS detected |
| Whitefish Bay Waterworks | WI2410597 | Milwaukee | 14,272 | <MRL | <MRL | 0 | No PFAS detected |
| Whitewater Waterworks | WI2650056 | Whitewater | 14,000 | <MRL | <MRL | 0 | No PFAS detected |
| Wis Rapids Water Works & Lighting Comm | WI7720108 | Wisconsin Rapids | 20,000 | <MRL | <MRL | 0 | No PFAS detected |
| Yorkville Utility Dist 1 | WI2521735 | Union Grove | 3,900 | <MRL | <MRL | 0 | No PFAS detected |
Highest single result for each system; PFOA and PFOS in ppt (ng/L). Entry-point samples, not tap water; screening comparisons, not compliance determinations.