Systems reaching a study comparison level
9.8%17 of 174 active community water systems with complete monitoring
All 174 systems had complete monitoring. 17 reached at least one study comparison level; 157 did not. “Study comparison level” means the dated EPA technical cutoff used in this January 2026 research release. It does not determine household exposure, health risk, or current legal compliance.
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ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
Compound summary
System counts in Wisconsin
Each count shows how many included water systems reached the named study level.
| Study comparison | Systems reaching level | Water systems included | Percent |
|---|---|---|---|
| PFOA: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 12 | 174 | 6.9% |
| PFOS: study level 4.05 ppt (April 2024 EPA level: 4 ppt) | 11 | 174 | 6.3% |
| PFHxS: study level 15 ppt (April 2024 EPA level: 10 ppt) | 3 | 174 | 1.7% |
| PFNA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 174 | 0.0% |
| HFPO-DA: study level 15 ppt (April 2024 EPA level: 10 ppt) | 0 | 174 | 0.0% |
| Hazard Index: study level 1.5 with at least two detected components (April 2024 EPA level: 1) | 3 | 174 | 1.7% |
System directory
Community water systems with complete monitoring
Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study comparison |
|---|---|---|---|---|---|
| ALLOUEZ WATERWORKS | WI4050455 | 13,923 | Surface water purchased | 1 | Below the study levels |
| ALTOONA WATERWORKS | WI6180280 | 9,627 | Ground water | 6 | Below the study levels |
| ANTIGO WATERWORKS | WI7340086 | 7,780 | Ground water | 1 | Below the study levels |
| APPLETON WATERWORKS | WI4450333 | 74,511 | Surface water | 1 | Below the study levels |
| ARENA WATERWORKS | WI1250073 | 877 | Ground water | 1 | Below the study levels |
| ASHWAUBENON WATERWORKS | WI4050456 | 17,730 | Surface water purchased | 1 | Below the study levels |
| BALDWIN WATERWORKS | WI6560119 | 4,440 | Ground water | 2 | Below the study levels |
| BARABOO WATERWORKS | WI1570085 | 12,703 | Ground water | 5 | Below the study levels |
| BARRON LIGHT & WATER DEPT | WI6030125 | 3,423 | Ground water | 4 | Below the study levels |
| BEAVER DAM WATER UTILITY | WI1140059 | 16,200 | Ground water | 1 | Below the study levels |
| BELLEVUE WATERWORKS | WI4050459 | 16,715 | Surface water purchased | 1 | Below the study levels |
| BELOIT CITY OF | WI1540112 | 36,677 | Ground water | 7 | Below the study levels |
| BERLIN WATERWORKS | WI4240216 | 5,524 | Ground water | 3 | Below the study levels |
| BLACK RIVER FALLS WATERWORKS | WI6270244 | 3,608 | Ground water | 4 | Below the study levels |
| BLOOMINGTON WATERWORKS | WI1220085 | 682 | Ground water | 1 | Below the study levels |
| BRILLION WATERWORKS | WI4080221 | 3,262 | Ground water | 3 | Below the study levels |
| BROOKFIELD WATER UTILITY | WI2680253 | 29,070 | Ground water | 17 | Below the study levels |
| BROWN DEER WATERWORKS | WI2410556 | 12,741 | Surface water purchased | 1 | Below the study levels |
| BURLINGTON WATERWORKS | WI2520177 | 11,043 | Ground water | 5 | Below the study levels |
| CALEDONIA WATER UTILITY - VILLAGE OF | WI2520184 | 21,819 | Surface water purchased | 2 | Below the study levels |
| CEDARBURG L & W COMMISSION | WI2460108 | 12,500 | Ground water | 4 | Below the study levels |
| CHIPPEWA FALLS WATERWORKS | WI6090456 | 13,375 | Ground water | 2 | Below the study levels |
| CLINTON WATERWORKS, WI | WI1540114 | 2,119 | Ground water | 2 | Below the study levels |
| CLINTONVILLE UTILITIES | WI4690391 | 4,635 | Ground water | 3 | Below the study levels |
| COLUMBUS WATER & LIGHT DEPARTMENT | WI1110038 | 5,173 | Ground water | 2 | Below the study levels |
| COMBINED LOCKS WATERWORKS | WI4450409 | 3,609 | Ground water purchased | 1 | Below the study levels |
| COTTAGE GROVE WATERWORKS | WI1130218 | 9,345 | Ground water | 3 | Below the study levels |
| CROSS PLAINS WATERWORKS | WI1130219 | 4,100 | Ground water | 3 | Below the study levels |
| CUDAHY WATERWORKS | WI2410169 | 18,659 | Surface water | 1 | Below the study levels |
| DARBOY SANITARY DIST 1 | WI4450117 | 13,024 | Ground water | 2 | Below the study levels |
| DE PERE WATER DEPARTMENT | WI4050453 | 25,660 | Surface water purchased | 1 | Below the study levels |
| DEFOREST WATERWORKS | WI1130221 | 10,500 | Ground water | 4 | Below the study levels |
| DELAVAN WATERWORKS | WI2650113 | 9,028 | Ground water | 3 | Below the study levels |
| DENMARK WATERWORKS | WI4050351 | 2,684 | Surface water purchased | 2 | Below the study levels |
| EAST TROY WATERWORKS | WI2650123 | 5,054 | Ground water | 4 | Below the study levels |
| EAU CLAIRE WATERWORKS | WI6180230 | 70,587 | Ground water | 1 | Below the study levels |
| EDGERTON WATERWORKS | WI1540119 | 5,512 | Ground water | 3 | Below the study levels |
| ELKHORN WATERWORKS | WI2650062 | 10,317 | Ground water | 3 | Below the study levels |
| ELLSWORTH WATERWORKS | WI6480239 | 3,304 | Ground water | 3 | Below the study levels |
| EVANSVILLE WATERWORKS | WI1540047 | 5,703 | Ground water | 2 | Below the study levels |
| FITCHBURG UTILITY DIST 1 | WI1130231 | 24,500 | Ground water | 4 | Below the study levels |
| FOND DU LAC WATERWORKS | WI4200469 | 44,678 | Ground water | 4 | Below the study levels |
| FORT ATKINSON WATERWORKS | WI1280103 | 12,390 | Ground water | 4 | Below the study levels |
| FORT MCCOY NORTH POST | WI6420302 | 10,000 | Ground water | 6 | Below the study levels |
| FOX CROSSING UTILITIES EAST-FORMERLY MENASHA TN OF | WI4710453 | 10,927 | Surface water purchased | 2 | Below the study levels |
| FOX CROSSING UTILITIES WEST-FORMERLY MENASHA TN OF | WI4710358 | 14,000 | Ground water | 4 | Below the study levels |
| FOX POINT WATERWORKS | WI2410584 | 6,808 | Surface water purchased | 1 | Below the study levels |
| FRANKLIN WATER UTILITY | WI2410563 | 22,500 | Surface water purchased | 1 | Below the study levels |
| GERMANTOWN WATER UTILITY | WI2670105 | 20,027 | Ground water | 6 | Below the study levels |
| GLENDALE WATERWORKS | WI2410168 | 12,883 | Surface water purchased | 1 | Below the study levels |
| GRAFTON WATERWORKS | WI2460111 | 12,269 | Ground water | 6 | Below the study levels |
| GRAND CHUTE TN SAN DIST 1 | WI4450429 | 21,583 | Surface water purchased | 1 | Below the study levels |
| GREEN BAY WATERWORKS | WI4050356 | 107,369 | Surface water | 1 | Below the study levels |
| GREENDALE WATERWORKS | WI2410571 | 14,393 | Surface water purchased | 1 | Below the study levels |
| GREENVILLE SANITARY DIST | WI4450278 | 11,340 | Ground water | 4 | Below the study levels |
| HARTFORD WATERWORKS, WI | WI2670110 | 15,805 | Ground water | 5 | Reached a study level |
| HARTLAND WATERWORKS | WI2680205 | 9,212 | Ground water | 5 | Reached a study level |
| HILBERT WATERWORKS | WI4080269 | 1,176 | Ground water | 2 | Below the study levels |
| HOLMEN WATERWORKS | WI6320306 | 10,147 | Ground water | 4 | Below the study levels |
| HORICON WATERWORKS | WI1140146 | 3,682 | Ground water | 3 | Below the study levels |
| HOWARD WATERWORKS | WI4050468 | 21,133 | Surface water purchased | 2 | Below the study levels |
| HUDSON WATERWORKS | WI6560087 | 18,558 | Ground water | 7 | Below the study levels |
| JACKSON WATERWORKS | WI2670111 | 7,844 | Ground water | 4 | Below the study levels |
| JANESVILLE WATER UTILITY | WI1540127 | 64,415 | Ground water | 3 | Below the study levels |
| JEFFERSON WATERWORKS | WI1280104 | 7,926 | Ground water | 3 | Below the study levels |
| KAUKAUNA UTILITIES | WI4450336 | 17,493 | Ground water | 3 | Below the study levels |
| KENOSHA WATER UTILITY | WI2300046 | 99,218 | Surface water | 1 | Below the study levels |
| KESHENA | 055295508 | 3,960 | Ground water | 1 | Below the study levels |
| KEWASKUM WATERWORKS | WI2670112 | 4,309 | Ground water | 4 | Reached a study level |
| KIEL WATERWORKS | WI4360427 | 3,932 | Ground water | 4 | Below the study levels |
| KIMBERLY WATERWORKS | WI4450342 | 7,608 | Ground water | 3 | Below the study levels |
| KRONENWETTER WATER & SEWER UTILITY | WI7371700 | 6,931 | Ground water | 2 | Below the study levels |
| LA CROSSE WATERWORKS | WI6320309 | 53,000 | Ground water | 10 | Reached a study level |
| LAKE GENEVA UTILITY COMMISSION | WI2650066 | 7,107 | Ground water | 2 | Reached a study level |
| LAKE HALLIE WATERWORKS VILLAGE OF | WI6090849 | 6,701 | Ground water | 4 | Below the study levels |
| LAKE MILLS WATERWORKS | WI1280108 | 6,211 | Ground water | 3 | Below the study levels |
| LAWRENCE WATERWORKS | WI4051625 | 5,398 | Surface water purchased | 1 | Below the study levels |
| LEDGEVIEW TN SANITARY DIST 2 | WI4051418 | 7,602 | Surface water purchased | 2 | Below the study levels |
| LITTLE CHUTE WATERWORKS | WI4450338 | 12,168 | Ground water | 3 | Below the study levels |
| MADISON WATER UTILITY | WI1130224 | 272,000 | Ground water | 20 | Below the study levels |
| MANITOWOC WATERWORKS | WI4360364 | 34,500 | Surface water | 1 | Below the study levels |
| MARINETTE WATERWORKS | WI4380395 | 10,968 | Surface water | 1 | Below the study levels |
| MARSHALL WATERWORKS | WI1130237 | 3,862 | Ground water | 3 | Below the study levels |
| MARSHFIELD UTILITIES | WI7720165 | 18,815 | Ground water | 3 | Reached a study level |
| MAYVILLE WATERWORKS | WI1140057 | 5,112 | Ground water | 4 | Below the study levels |
| MCFARLAND WATERWORKS | WI1130241 | 9,676 | Ground water | 3 | Below the study levels |
| MEDFORD WATERWORKS | WI8610125 | 4,318 | Ground water | 6 | Below the study levels |
| MENASHA ELEC & WATER UTIL | WI4710334 | 15,144 | Surface water | 1 | Below the study levels |
| MENOMONIE WATERWORKS | WI6170268 | 15,950 | Ground water | 3 | Below the study levels |
| MEQUON WATER UTILITY | WI2460112 | 11,152 | Surface water purchased | 2 | Below the study levels |
| MERRILL WATERWORKS | WI7350123 | 9,661 | Ground water | 2 | Below the study levels |
| MIDDLETON WATERWORKS | WI1130242 | 23,868 | Ground water | 6 | Below the study levels |
| MILTON WATERWORKS | WI1540130 | 5,588 | Ground water | 4 | Below the study levels |
| MILWAUKEE WATERWORKS | WI2410100 | 626,000 | Surface water | 2 | Below the study levels |
| MONROE WATERWORKS | WI1230078 | 10,780 | Ground water | 5 | Below the study levels |
| MT HOREB WATERWORKS | WI1130247 | 7,756 | Ground water | 4 | Below the study levels |
| MUKWONAGO WATERWORKS | WI2680209 | 8,190 | Ground water | 2 | Below the study levels |
| MUSKEGO WATER UTILITY | WI2681741 | 8,150 | Ground water | 8 | Below the study levels |
| NEENAH WATERWORKS | WI4710348 | 27,506 | Surface water | 1 | Below the study levels |
| NEW BERLIN WATER UTILITY | WI2680217 | 27,899 | Surface water purchased | 1 | Below the study levels |
| NEW LONDON WATERWORKS | WI4690398 | 7,187 | Ground water | 7 | Below the study levels |
| NEW RICHMOND WATERWORKS | WI6560126 | 10,824 | Ground water | 5 | Below the study levels |
| NORTH FOND DU LAC WATERWORKS | WI4200405 | 5,414 | Ground water | 1 | Below the study levels |
| NORTH SHORE WATER COMMISSION | WI2413515 | 35,598 | Surface water | 1 | Below the study levels |
| OAK CREEK WATERWORKS | WI2410172 | 32,104 | Surface water | 1 | Below the study levels |
| OCONOMOWOC WATERWORKS | WI2680227 | 15,805 | Ground water | 4 | Below the study levels |
| OMRO WATERWORKS | WI4710357 | 3,629 | Ground water | 3 | Below the study levels |
| ONALASKA WATERWORKS | WI6320327 | 18,000 | Ground water | 4 | Below the study levels |
| OREGON WATERWORKS | WI1130251 | 11,200 | Ground water | 3 | Below the study levels |
| OSHKOSH WATERWORKS | WI4710457 | 63,000 | Surface water | 1 | Below the study levels |
| PALMYRA WATERWORKS | WI1280112 | 1,756 | Ground water | 2 | Reached a study level |
| PESHTIGO WATERWORKS | WI4380442 | 3,420 | Ground water | 3 | Below the study levels |
| PEWAUKEE CITY WATER AND SEWER UTILITY | WI2680214 | 8,671 | Ground water | 8 | Reached a study level |
| PLATTEVILLE WATERWORKS | WI1220115 | 12,268 | Ground water | 3 | Below the study levels |
| PLEASANT PRAIRIE WATER UTILITY | WI2300167 | 10,754 | Surface water purchased | 1 | Below the study levels |
| PLOVER WATERWORKS | WI7500726 | 13,486 | Ground water | 3 | Below the study levels |
| PLYMOUTH UTILITIES | WI4600446 | 8,964 | Ground water | 7 | Below the study levels |
| PORT WASHINGTON WATERWORKS | WI2460054 | 12,853 | Surface water | 1 | Below the study levels |
| PORTAGE WATERWORKS | WI1110039 | 10,437 | Ground water | 2 | Below the study levels |
| PRAIRIE DU SAC WATERWORKS | WI1570100 | 4,006 | Ground water | 2 | Below the study levels |
| PRESCOTT WATERWORKS | WI6480243 | 4,258 | Ground water | 2 | Reached a study level |
| PULASKI WATERWORKS | WI4050355 | 4,040 | Ground water | 2 | Below the study levels |
| RACINE WATERWORKS | WI2520062 | 105,100 | Surface water | 1 | Below the study levels |
| REEDSBURG WATERWORKS | WI1570102 | 9,984 | Ground water | 5 | Below the study levels |
| RHINELANDER WATER & WASTEWATER | WI7440126 | 8,234 | Ground water | 2 | Reached a study level |
| RIB MOUNTAIN SANITARY DIST | WI7370660 | 6,398 | Ground water | 4 | Reached a study level |
| RICE LAKE WATERWORKS | WI6030138 | 9,012 | Ground water | 4 | Below the study levels |
| RICHLAND CENTER WATERWORKS | WI1530068 | 5,100 | Ground water | 3 | Below the study levels |
| RIPON WATER UTILITY | WI4200476 | 7,716 | Ground water | 4 | Below the study levels |
| RIVER FALLS WATERWORKS | WI6480246 | 16,000 | Ground water | 5 | Below the study levels |
| SAUK CITY WATERWORKS | WI1570105 | 3,518 | Ground water | 2 | Below the study levels |
| SAUKVILLE WATERWORKS | WI2460134 | 4,268 | Ground water | 5 | Reached a study level |
| SCHOFIELD WATERWORKS | WI7370162 | 2,205 | Ground water | 2 | Reached a study level |
| SEYMOUR WATERWORKS | WI4450337 | 3,601 | Ground water | 2 | Below the study levels |
| SHAWANO LK SAN DIST 1 | WI4590457 | 4,950 | Ground water | 3 | Below the study levels |
| SHAWANO WATERWORKS | WI4590456 | 9,610 | Ground water | 3 | Below the study levels |
| SHEBOYGAN FALLS UTILITIES | WI4600455 | 8,687 | Surface water purchased | 1 | Below the study levels |
| SHEBOYGAN TN WATERWORKS | WI4600403 | 4,596 | Ground water | 3 | Below the study levels |
| SHEBOYGAN WATER UTILITIES | WI4600354 | 49,931 | Surface water | 1 | Below the study levels |
| SHOREWOOD WATERWORKS | WI2410607 | 13,535 | Surface water purchased | 1 | Below the study levels |
| SHULLSBURG WATERWORKS | WI1330076 | 1,222 | Ground water | 2 | Below the study levels |
| SLINGER WATER UTILITY | WI2670116 | 5,659 | Ground water | 3 | Below the study levels |
| SOUTH MILWAUKEE WATERWORKS | WI2410144 | 21,340 | Surface water | 1 | Below the study levels |
| SOUTH-CENTRAL WATER SYSTEM | 055295003 | 2,805 | Ground water | 1 | Below the study levels |
| SPARTA WATERWORKS | WI6420297 | 10,025 | Ground water | 5 | Below the study levels |
| STANLEY WATERWORKS | WI6090462 | 3,500 | Ground water | 3 | Below the study levels |
| STEVENS POINT WATERWORKS | WI7500141 | 26,717 | Ground water | 2 | Below the study levels |
| STOUGHTON WATERWORKS | WI1130078 | 13,078 | Ground water | 4 | Below the study levels |
| STURGEON BAY WATERWORKS | WI4150526 | 9,700 | Ground water | 5 | Reached a study level |
| SUAMICO WATERWORKS | WI4051031 | 4,697 | Ground water | 2 | Below the study levels |
| SUN PRAIRIE UTILITIES | WI1130258 | 39,300 | Ground water | 7 | Below the study levels |
| SUPERIOR WATER LIGHT & POWER COMPANY | WI8160147 | 26,084 | Surface water | 1 | Below the study levels |
| SUSSEX VILLAGE HALL & WATER UTILITY | WI2680233 | 11,750 | Ground water | 4 | Below the study levels |
| TOMAH WATERWORKS | WI6420254 | 9,192 | Ground water | 5 | Below the study levels |
| TOMAHAWK WATERWORKS | WI7350127 | 3,180 | Ground water | 2 | Reached a study level |
| TWO RIVERS WATERWORKS | WI4360436 | 11,270 | Surface water | 1 | Below the study levels |
| UNION GROVE WATERWORKS | WI2520200 | 4,900 | Ground water | 3 | Below the study levels |
| VERONA WATERWORKS | WI1130259 | 14,030 | Ground water | 5 | Below the study levels |
| VIROQUA WATERWORKS | WI6630263 | 4,362 | Ground water | 3 | Below the study levels |
| WATERFORD WATERWORKS | WI2520202 | 5,368 | Ground water | 3 | Below the study levels |
| WATERTOWN WATERWORKS | WI1280044 | 23,945 | Ground water | 3 | Below the study levels |
| WAUKESHA WATER UTILITY | WI2680238 | 70,718 | Surface water purchased | 7 | Below the study levels |
| WAUNAKEE WATERWORKS | WI1130265 | 14,879 | Ground water | 4 | Below the study levels |
| WAUPACA WATERWORKS | WI4690402 | 6,062 | Ground water | 6 | Reached a study level |
| WAUPUN CORRECTIONAL INST | WI1140142 | 3,706 | Ground water | 2 | Below the study levels |
| WAUPUN UTILITIES | WI1140131 | 8,056 | Ground water | 1 | Below the study levels |
| WAUSAU WATERWORKS | WI7370102 | 39,994 | Ground water | 2 | Below the study levels |
| WAUWATOSA WATERWORKS | WI2410596 | 49,064 | Surface water purchased | 1 | Below the study levels |
| WEST ALLIS WATERWORKS | WI2410595 | 63,240 | Surface water purchased | 1 | Below the study levels |
| WEST SALEM WATERWORKS | WI6320334 | 5,045 | Ground water | 3 | Below the study levels |
| WESTON MUNICIPAL UTILITIES | WI7370163 | 16,000 | Ground water | 7 | Reached a study level |
| WHITEFISH BAY WATERWORKS | WI2410597 | 14,272 | Surface water purchased | 1 | Below the study levels |
| WHITEWATER WATERWORKS | WI2650056 | 14,000 | Ground water | 5 | Below the study levels |
| WIS RAPIDS WATER WORKS & LIGHTING COMM | WI7720108 | 20,000 | Ground water | 1 | Below the study levels |
How the count works
What is included
Each active community water system with complete monitoring is counted once, even if it is linked with several ZIP codes. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Wisconsin's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.