Community Water System · PWS WI2650057

Darien Waterworks

Darien, Wisconsin 53114 - drinking water served from groundwater sources to 1,573 people, tracked in EPA SDWIS and UCMR5.

Compiled by PlainWater Editorial, Drinking Water Quality Editorial Team · May 15, 2026

1,573
People served: 153
EPA violations: 7
Health-based: Untested
UCMR5 result

The verdict

EPA records 153 drinking-water violations at Darien Waterworks, 5% of them health-based - above the Wisconsin per-system average.

153
Total EPA violations on record: 5%
Health-based (MCL / treatment failure): 1,573
People served by this system: N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Darien Waterworks

Darien Waterworks is a local-owned community water system that delivers drinking water to 1,573 residents in Darien, Wisconsin (Walworth County) through 582 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 153 total violations for this system , of which 7 (5%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 136 monitoring and reporting violations are on file. The most recent violation on record dates to 2020.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 7 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%).

Darien Waterworks's 153 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

1,573

Total Violations

153

Health-Based Violations

Water Source

Groundwater

System Details

System Type: Community
Owner Type: Local
Connections: 582
County: Walworth
School/Daycare: No
MCL Violations: 7
Monitoring Violations: 136
Treatment Tech Violations: 0

Violation History

Contaminant violations recorded by EPA.

Contaminant	Category	Count	Latest
Coliform (TCR)	MCL	7	1995
Consumer Confidence Rule	Other	6	2000
cis-1,2-Dichloroethylene	MR	6	2001
o-Dichlorobenzene	MR	6	2001
p-Dichlorobenzene	MR	6	2001
Vinyl chloride	MR	6	2001
1,2-Dichloroethane	MR	6	2001
1,1,1-Trichloroethane	MR	6	2001
1,2-Dichloropropane	MR	6	2001
Trichloroethylene	MR	6	2001
CHLOROBENZENE	MR	6	2001
Benzene	MR	6	2001
Ethylbenzene	MR	6	2001
Styrene	MR	6	2001
Carbon tetrachloride	MR	6	2001
1,2,4-Trichlorobenzene	MR	6	2001
1,1-Dichloroethylene	MR	6	2001
Tetrachloroethylene	MR	6	2001
Toluene	MR	6	2001
DICHLOROMETHANE	MR	6	2001
trans-1,2-Dichloroethylene	MR	6	2001
1,1,2-Trichloroethane	MR	6	2001
Lead and Copper Rule	MR	6	2020
Xylenes, Total	MR	6	2001
Coliform (TCR)	MR	4	1997

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 Darien 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 WI2650057 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 Darien 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
2020	Lead and Copper Rule	MR	6	SDWIS / WI2650057 / 5000
2001	cis-1,2-Dichloroethylene	MR	6	SDWIS / WI2650057 / 2380
2001	o-Dichlorobenzene	MR	6	SDWIS / WI2650057 / 2968
2001	p-Dichlorobenzene	MR	6	SDWIS / WI2650057 / 2969
2001	Vinyl chloride	MR	6	SDWIS / WI2650057 / 2976
2001	1,2-Dichloroethane	MR	6	SDWIS / WI2650057 / 2980
2001	1,1,1-Trichloroethane	MR	6	SDWIS / WI2650057 / 2981
2001	1,2-Dichloropropane	MR	6	SDWIS / WI2650057 / 2983
2001	Trichloroethylene	MR	6	SDWIS / WI2650057 / 2984
2001	CHLOROBENZENE	MR	6	SDWIS / WI2650057 / 2989
2001	Benzene	MR	6	SDWIS / WI2650057 / 2990
2001	Ethylbenzene	MR	6	SDWIS / WI2650057 / 2992
2001	Styrene	MR	6	SDWIS / WI2650057 / 2996
2001	Carbon tetrachloride	MR	6	SDWIS / WI2650057 / 2982
2001	1,2,4-Trichlorobenzene	MR	6	SDWIS / WI2650057 / 2378

How Darien Waterworks Compares

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

Metric	Darien Waterworks	Wisconsin avg	Federal benchmark
Total violations	153	26	SDWA compliance, any non-zero count is a recorded breach
Health-based violations	7	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	1,573	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 Darien Waterworks water safe to drink? ▼

Darien Waterworks (PWS ID: WI2650057) has 153 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 1,573 people using Groundwater sources.

How many people does Darien Waterworks serve? ▼

Darien Waterworks serves 1,573 people in Darien, Wisconsin. It is a Local-owned system using Groundwater water sources with 582 service connections.

What type of violations does Darien Waterworks have? ▼

Darien Waterworks has 153 total violations: 7 health-based violations (MCL exceedances or treatment failures), 136 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.

Has PFAS been detected in Darien Waterworks water? ▼

No PFAS testing data is available for Darien Waterworks under the EPA's UCMR5 monitoring program.

What water source does Darien Waterworks use? ▼

Darien 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.