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Community Water System · PWS WI4050351

Denmark Waterworks

Denmark, Wisconsin 54208 - drinking water served from surface water sources to 2,684 people, tracked in EPA SDWIS and UCMR5.

2,684
People served
30
EPA violations
8
Health-based
No PFAS
UCMR5 result

The verdict

EPA records 30 drinking-water violations at Denmark Waterworks, 27% of them health-based - above the Wisconsin per-system average.

30
Total EPA violations on record
27%
Health-based (MCL / treatment failure)
2,684
People served by this system
0
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Denmark Waterworks

Denmark Waterworks is a local-owned community water system that delivers drinking water to 2,684 residents in Denmark, Wisconsin (Brown County) through 976 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 30 total violations for this system , of which 8 (27%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 14 monitoring and reporting violations are on file. The most recent violation on record dates to 2024.

The most frequently cited contaminant at this system is Lead and Copper Rule, recorded in 8 violations (MR). This system was sampled under EPA's UCMR5 PFAS monitoring program and no PFAS compounds were detected above the minimum reporting level.

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%).

Denmark Waterworks's 30 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.

Population Served
2,684
Total Violations
30
Health-Based Violations
8
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
976
County
Brown
School/Daycare
No
MCL Violations
0
Monitoring Violations
14
Treatment Tech Violations
8

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Lead and Copper Rule MR 8 2011
Lead and Copper Rule TT 6 2005
Public Notice Other 4 2024
Revised Total Coliform Rule MON 4 2024
Coliform (TCR) MR 2 1992
Consumer Confidence Rule Other 2 2009
LEAD AND COPPER RULE REVISIONS TT 2 2024

PFAS Testing Results (UCMR5)

Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 0 of 116 samples detected PFAS.

Contaminant Date Result MRL Status
PFEESA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
9Cl-PF3ONS 6/19/2023 <2.00 ppt 2.00 ppt Not Detected
ADONA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
HFPO-DA 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
PFBA 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
PFMPA 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
PFMBA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
11Cl-PF3OUdS 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
PFHxS 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
NFDHA 6/19/2023 <20.00 ppt 20.00 ppt Not Detected
PFPeS 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
PFHpS 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFTA 6/19/2023 <8.00 ppt 8.00 ppt Not Detected
NMeFOSAA 6/19/2023 <6.00 ppt 6.00 ppt Not Detected
PFHpA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFBS 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFOS 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
PFTrDA 6/19/2023 <7.00 ppt 7.00 ppt Not Detected
PFUnA 6/19/2023 <2.00 ppt 2.00 ppt Not Detected
PFNA 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
NEtFOSAA 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
PFOA 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
PFDA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFDoA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFHxA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFMBA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFBA 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
6:2 FTS 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
4:2 FTS 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
8:2 FTS 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
HFPO-DA 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
ADONA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFPeA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFUnA 6/19/2023 <2.00 ppt 2.00 ppt Not Detected
PFEESA 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
NFDHA 6/19/2023 <20.00 ppt 20.00 ppt Not Detected
PFPeS 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
PFHpS 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFMPA 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
PFOS 6/19/2023 <4.00 ppt 4.00 ppt Not Detected
PFTA 6/19/2023 <8.00 ppt 8.00 ppt Not Detected
PFTrDA 6/19/2023 <7.00 ppt 7.00 ppt Not Detected
NEtFOSAA 6/19/2023 <5.00 ppt 5.00 ppt Not Detected
NMeFOSAA 6/19/2023 <6.00 ppt 6.00 ppt Not Detected
PFBS 6/19/2023 <3.00 ppt 3.00 ppt Not Detected
PFHpA 6/19/2023 <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 Denmark 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 WI4050351 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 Denmark 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
2024 Public Notice Other 4 SDWIS / WI4050351 / 7500
2024 Revised Total Coliform Rule MON 4 SDWIS / WI4050351 / 8000
2024 LEAD AND COPPER RULE REVISIONS TT 2 SDWIS / WI4050351 / 5200
2011 Lead and Copper Rule MR 8 SDWIS / WI4050351 / 5000
2009 Consumer Confidence Rule Other 2 SDWIS / WI4050351 / 7000
2005 Lead and Copper Rule TT 6 SDWIS / WI4050351 / 5000
1992 Coliform (TCR) MR 2 SDWIS / WI4050351 / 3100

How Denmark Waterworks Compares

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

Metric Denmark Waterworks Wisconsin avg Federal benchmark
Total violations 30 26 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 8 5.3 Indicates a contaminant exceeded a federal MCL
PFAS detection None 38.6% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 2,684 467 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 Denmark Waterworks water safe to drink? ▼
Denmark Waterworks (PWS ID: WI4050351) has 30 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 2,684 people using Surface Water sources.
How many people does Denmark Waterworks serve? ▼
Denmark Waterworks serves 2,684 people in Denmark, Wisconsin. It is a Local-owned system using Surface Water water sources with 976 service connections.
What type of violations does Denmark Waterworks have? ▼
Denmark Waterworks has 30 total violations: 8 health-based violations (MCL exceedances or treatment failures), 14 monitoring/reporting violations, and 8 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Denmark Waterworks water? ▼
No. Denmark Waterworks was tested for PFAS under the EPA's UCMR5 monitoring program and no PFAS contamination was detected.
What water source does Denmark Waterworks use? ▼
Denmark Waterworks uses Surface Water 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.