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Drinking water / WI

PFAS in Wisconsin drinking water

202 Wisconsin public water systems tested under UCMR5. 52 detected at least one PFAS compound; 150 detected none at the reporting thresholds. Values are the highest single result per compound, in ng/L (parts per trillion). The federal limit for PFOA and PFOS is 4 ng/L.

Water systemServesHighest results (ng/L)Reading
CONCOR TOOL & MACHINE INC

WI8581084

SawyerPFOA 8.5 *PFOS 6.7 *PFBS 5PFHxA 3.2above final limit
HARTFORD WATERWORKS, WI

WI2670110

WashingtonPFOA 6.8 *PFHxS 6.1PFOS 5.5 *PFBS 3.2above final limit
HARTLAND WATERWORKS

WI2680205

WaukeshaPFBS 11PFBA 5.1PFPeA 4.6PFOS 4.6 *above final limit
KEWASKUM WATERWORKS

WI2670112

WashingtonPFOA 15 *PFBS 6.6above final limit
LA CROSSE WATERWORKS

WI6320309

La CrossePFBA 21PFBS 15PFHxS 8.4PFOS 5.5 *above final limit
LAKE GENEVA UTILITY COMMISSION

WI2650066

WalworthPFBS 6PFOA 4.7 *PFHxS 3.9above final limit
MARSHFIELD UTILITIES

WI7720165

WoodPFHxS 14PFOS 14 *PFPeA 14PFHxA 12above final limit
MEDFORD WATERWORKS

WI8610125

TaylorPFBA 5.4PFHxS 5.2PFOA 4.1 *above final limit
PALMYRA WATERWORKS

WI1280112

JeffersonPFOS 6.2 *PFHxS 3.2above final limit
PEWAUKEE CITY WATER AND SEWER UTILITY

WI2680214

WaukeshaPFHxS 69PFHxA 406:2 FTS 35PFBS 27above final limit
PRAIRIE DU CHIEN WATERWORKS

WI6120250

CrawfordPFOS 39 *PFHxS 11above final limit
PRESCOTT WATERWORKS

WI6480243

PiercePFBA 280PFHxS 18PFPeA 10PFOA 9.9 *above final limit
RHINELANDER WATER & WASTEWATER

WI7440126

OneidaPFHxA 11PFPeA 9.6PFOA 6.8 *PFHpA 6.4above final limit
RIB MOUNTAIN SANITARY DIST

WI7370660

MarathonPFPeA 23PFBA 16PFOS 9.4 *PFHxS 9.2above final limit
SAUKVILLE WATERWORKS

WI2460134

OzaukeePFHxS 73PFOS 31 *PFPeS 30PFBS 29above final limit
SCHOFIELD WATERWORKS

WI7370162

MarathonPFBS 11PFPeA 9.8PFHxA 7.8PFHxS 6.2above final limit
STURGEON BAY WATERWORKS

WI4150526

DoorPFHxS 13PFOS 4.2 *above final limit
TOMAHAWK WATERWORKS

WI7350127

LincolnPFOA 21 *PFPeA 7.9PFBA 7.8PFHxA 7.5above final limit
WAUPACA WATERWORKS

WI4690402

WaupacaPFBS 7.9PFBA 5PFOS 4.3 *above final limit
WEST BEND WATERWORKS

WI2670120

WashingtonPFOA 6.5 *PFBS 3.9above final limit
WESTON MUNICIPAL UTILITIES

WI7370163

MarathonPFBS 22PFOS 13 *PFOA 5.9 *PFHxS 5.8above final limit
APPLETON WATERWORKS

WI4450333

OutagamiePFBA 5.9detected
BELOIT CITY OF

WI1540112

RockPFBS 3detected
BLACK RIVER FALLS WATERWORKS

WI6270244

JacksonPFBA 6.8detected
BROOKFIELD WATER UTILITY

WI2680253

WaukeshaPFBS 4.7PFPeA 4.4PFHxA 3.3PFHxS 3.2detected
CHIPPEWA FALLS WATERWORKS

WI6090456

ChippewaPFBS 4.8detected
EAST TROY WATERWORKS

WI2650123

WalworthPFBS 4.8detected
EAU CLAIRE WATERWORKS

WI6180230

Eau ClairePFHxS 11PFBS 3detected
ELLSWORTH WATERWORKS

WI6480239

PiercePFBA 41detected
HARRISON UTILITIES - FKA WAVERLY SD

WI4080076

CalumetPFBA 6.7detected
HOLMEN WATERWORKS

WI6320306

La CrossePFPeA 3.3detected
HUDSON WATERWORKS

WI6560087

St. CroixPFBA 32detected
MADISON WATER UTILITY

WI1130224

DanePFBA 46.5PFHxS 7.3detected
MCFARLAND WATERWORKS

WI1130241

DanePFHxS 3.7detected
MONONA WATERWORKS

WI1130245

DanePFBA 11PFHxS 5.4PFBS 5.3PFPeA 4.6detected
MT HOREB WATERWORKS

WI1130247

DanePFPeA 4.4PFHxS 3.3detected
NEW LONDON WATERWORKS

WI4690398

WaupacaPFPeA 3.7detected
NEW RICHMOND WATERWORKS

WI6560126

St. CroixPFBA 6.4detected
OCONOMOWOC WATERWORKS

WI2680227

WaukeshaPFBA 5.4PFBS 4.6detected
ONALASKA WATERWORKS

WI6320327

La CrossePFBS 4.2detected
PEWAUKEE VILLAGE WATERWORKS

WI2680229

WaukeshaPFBA 8PFPeA 5.4detected
PLOVER WATERWORKS

WI7500726

PortagePFBA 7.5detected
PORTAGE WATERWORKS

WI1110039

ColumbiaPFHxS 8.1detected
REEDSBURG WATERWORKS

WI1570102

SaukPFHxS 4.4detected
SHAWANO LK SAN DIST 1

WI4590457

ShawanoPFBA 5.9detected
SHEBOYGAN TN WATERWORKS

WI4600403

SheboyganPFHxS 12PFPeA 4.4PFBS 4.2PFHxA 3.2detected
SLINGER WATER UTILITY

WI2670116

WashingtonPFPeA 7PFHxS 5.7PFHxA 4.8detected
STOUGHTON WATERWORKS

WI1130078

DanePFHxS 3.6detected
TOMAH WATERWORKS

WI6420254

MonroePFHxS 5.7PFPeA 5.1PFHxA 3.9detected
TOWN OF BROOKFIELD SAN DIST 4

WI2680239

WaukeshaPFBS 7.1PFBA 6.3detected
VERONA WATERWORKS

WI1130259

DanePFBS 3.5detected
WAUSAU WATERWORKS

WI7370102

MarathonPFBA 5detected

* exceeds the final federal MCL for that compound. Detections of compounds whose limits EPA proposed to rescind in May 2026 are shown for information.

Systems with no PFAS detected

150 tested systems reported no PFAS above the laboratory reporting limits. Each has its own page with its sampling detail.

A detection at the system level does not tell you what reaches one specific tap: levels vary by entry point, treatment train and plumbing. A certified lab test of your own tap settles it. Testing and treatment options