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Community Water System · PWS WI6630257

Hillsboro Waterworks

Hillsboro, Wisconsin 54634 - drinking water served from groundwater sources to 1,325 people, tracked in EPA SDWIS and UCMR5.

1,325
People served
93
EPA violations
55
Health-based
Untested
UCMR5 result

The verdict

EPA records 93 drinking-water violations at Hillsboro Waterworks, 59% of them health-based - above the Wisconsin per-system average.

93
Total EPA violations on record
59%
Health-based (MCL / treatment failure)
1,325
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Hillsboro Waterworks

Hillsboro Waterworks is a local-owned community water system that delivers drinking water to 1,325 residents in Hillsboro, Wisconsin (Vernon County) through 661 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 93 total violations for this system , of which 55 (59%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 10 monitoring and reporting violations are on file. The most recent violation on record dates to 2023.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 21 violations (MCL, health-based). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

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%).

Hillsboro Waterworks's 93 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
1,325
Total Violations
93
Health-Based Violations
55
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
661
County
Vernon
School/Daycare
No
MCL Violations
21
Monitoring Violations
10
Treatment Tech Violations
34

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MCL 21 1998
Groundwater Rule TT 20 2019
Public Notice Other 15 2019
Lead and Copper Rule TT 14 2023
Groundwater Rule Other 8 2019
Coliform (TCR) MR 6 2003
Lead and Copper Rule MR 4 2017
Consumer Confidence Rule Other 4 2023

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 Hillsboro 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 WI6630257 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 Hillsboro 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
2023 Lead and Copper Rule TT 14 SDWIS / WI6630257 / 5000
2023 Consumer Confidence Rule Other 4 SDWIS / WI6630257 / 7000
2019 Groundwater Rule TT 20 SDWIS / WI6630257 / 0700
2019 Public Notice Other 15 SDWIS / WI6630257 / 7500
2019 Groundwater Rule Other 8 SDWIS / WI6630257 / 0700
2017 Lead and Copper Rule MR 4 SDWIS / WI6630257 / 5000
2003 Coliform (TCR) MR 6 SDWIS / WI6630257 / 3100
1998 Coliform (TCR) MCL 21 SDWIS / WI6630257 / 3100

How Hillsboro Waterworks Compares

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

Metric Hillsboro Waterworks Wisconsin avg Federal benchmark
Total violations 93 26 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 55 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 1,325 467 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 Hillsboro Waterworks water safe to drink? ▼
Hillsboro Waterworks (PWS ID: WI6630257) has 93 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,325 people using Groundwater sources.
How many people does Hillsboro Waterworks serve? ▼
Hillsboro Waterworks serves 1,325 people in Hillsboro, Wisconsin. It is a Local-owned system using Groundwater water sources with 661 service connections.
What type of violations does Hillsboro Waterworks have? ▼
Hillsboro Waterworks has 93 total violations: 55 health-based violations (MCL exceedances or treatment failures), 10 monitoring/reporting violations, and 34 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Hillsboro Waterworks water? ▼
No PFAS testing data is available for Hillsboro Waterworks under the EPA's UCMR5 monitoring program.
What water source does Hillsboro Waterworks use? ▼
Hillsboro 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. 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.