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Community Water System · PWS WI6420254

Tomah Waterworks

Tomah, Wisconsin 54660-0151 - drinking water served from groundwater sources to 9,192 people, tracked in EPA SDWIS and UCMR5.

9,192
People served
127
EPA violations
117
Health-based
3 PFAS
UCMR5 result

The verdict

EPA records 127 drinking-water violations at Tomah Waterworks, 92% of them health-based - above the Wisconsin per-system average, and UCMR5 testing detected 3 PFAS compounds.

127
Total EPA violations on record
92%
Health-based (MCL / treatment failure)
9,192
People served by this system
3
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Tomah Waterworks

Tomah Waterworks is a local-owned community water system that delivers drinking water to 9,192 residents in Tomah, Wisconsin (Monroe County) through 3,139 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 127 total violations for this system , of which 117 (92%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. The most recent violation on record dates to 2025.

The most frequently cited contaminant at this system is Combined Radium (-226 and -228), recorded in 105 violations (MCL, health-based). Under EPA's UCMR5 PFAS monitoring program, 3 PFAS compounds were detected in samples collected from this system, with a maximum reported concentration of 5.7 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.

Across Wisconsin, EPA tracks 10,988 public water systems serving 5,131,439 people, with 285,161 cumulative violations and 58,688 health-based violations on record. About 72% of systems in the state carry at least one violation, and state-wide the average per system is 26 violations. Statewide, 78 of 202 UCMR5-tested systems have reported PFAS detections (38.6%).

Tomah Waterworks's 127 violations sit above the Wisconsin average.

All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

PFAS Detected

3 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.

Population Served
9,192
Total Violations
127
Health-Based Violations
117
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
3,139
County
Monroe
School/Daycare
No
MCL Violations
117
Monitoring Violations
0
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Combined Radium (-226 and -228) MCL 105 2018
Public Notice Other 8 2017
Nitrate MCL 5 2025
Gross Alpha, Excl. Radon and U MCL 5 1996
ETHYLENE DIBROMIDE MCL 2 1993

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 7 of 290 samples detected PFAS.

Contaminant Date Result MRL Status
PFUnA 9/25/2023 <2.00 ppt 2.00 ppt Not Detected
PFDoA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFDA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFOA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFNA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFHxS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFBS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
NMeFOSAA 9/25/2023 <6.00 ppt 6.00 ppt Not Detected
NEtFOSAA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFTrDA 9/25/2023 <7.00 ppt 7.00 ppt Not Detected
PFTA 9/25/2023 <8.00 ppt 8.00 ppt Not Detected
11Cl-PF3OUdS 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFMBA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeS 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFEESA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFMPA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
9Cl-PF3ONS 9/25/2023 <2.00 ppt 2.00 ppt Not Detected
4:2 FTS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
6:2 FTS 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
ADONA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
NFDHA 9/25/2023 <20.00 ppt 20.00 ppt Not Detected
PFHxS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFDoA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFDA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFOA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFNA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFBA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFHpA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFBS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFOS 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
PFMPA 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
NMeFOSAA 9/25/2023 <6.00 ppt 6.00 ppt Not Detected
NEtFOSAA 9/25/2023 <5.00 ppt 5.00 ppt Not Detected
PFTrDA 9/25/2023 <7.00 ppt 7.00 ppt Not Detected
PFTA 9/25/2023 <8.00 ppt 8.00 ppt Not Detected
PFHpS 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeS 9/25/2023 <4.00 ppt 4.00 ppt Not Detected
NFDHA 9/25/2023 <20.00 ppt 20.00 ppt Not Detected
PFEESA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
ADONA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 9/25/2023 <3.00 ppt 3.00 ppt Not Detected

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Tomah Waterworks.

Federal Source of Truth

EPA SDWIS, Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID WI6420254 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Wisconsin Drinking Water Authority

Wisconsin DNR, Drinking Water and Groundwater is the primacy agency that licenses and inspects Tomah Waterworks under EPA-delegated authority.

Open WI regulator portal

Source: Wisconsin DNR, Drinking Water and Groundwater

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
2025 Nitrate MCL 5 SDWIS / WI6420254 / 1040
2018 Combined Radium (-226 and -228) MCL 105 SDWIS / WI6420254 / 4010
2017 Public Notice Other 8 SDWIS / WI6420254 / 7500
1996 Gross Alpha, Excl. Radon and U MCL 5 SDWIS / WI6420254 / 4000
1993 ETHYLENE DIBROMIDE MCL 2 SDWIS / WI6420254 / 2946

How Tomah Waterworks Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric Tomah Waterworks Wisconsin avg Federal benchmark
Total violations 127 26 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 117 5.3 Indicates a contaminant exceeded a federal MCL
PFAS detection 3 compounds 38.6% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 9,192 467 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 10,988 regulated public water systems in Wisconsin.

Federal MCL reference, Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Tomah Waterworks water safe to drink? ▼
Tomah Waterworks (PWS ID: WI6420254) has 127 recorded violations in the EPA SDWIS database. PFAS contamination has been detected in UCMR5 testing, with 3 PFAS compounds found. This system serves 9,192 people using Groundwater sources.
How many people does Tomah Waterworks serve? ▼
Tomah Waterworks serves 9,192 people in Tomah, Wisconsin. It is a Local-owned system using Groundwater water sources with 3,139 service connections.
What type of violations does Tomah Waterworks have? ▼
Tomah Waterworks has 127 total violations: 117 health-based violations (MCL exceedances or treatment failures), 0 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Tomah Waterworks water? ▼
Yes. UCMR5 testing detected 3 PFAS compounds in Tomah Waterworks's water supply: PFHxS, PFPeA, PFHxA. PFAS are persistent "forever chemicals" that do not break down in the environment.
What water source does Tomah Waterworks use? ▼
Tomah Waterworks uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. PFAS data from EPA UCMR5 monitoring program (2023-2025). This data is provided for informational purposes only.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.