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POTOSI WATERWORKS

PWS ID: WI1220117 · POTOSI, Wisconsin 53820-0045

POTOSI WATERWORKS serves 718 people in POTOSI, Wisconsin using Groundwater water sources. It has 83 recorded EPA violations, including 8 health-based violations. No PFAS contamination was detected in UCMR5 testing.

Water Quality Snapshot: POTOSI WATERWORKS

POTOSI WATERWORKS is a local-owned community water system that delivers drinking water to 718 residents in POTOSI, Wisconsin (Grant County) through 265 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 83 total violations for this system , of which 8 (10%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 73 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 Coliform (TCR), recorded in 7 violations (MR). 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. POTOSI WATERWORKS's 83 violations sit above the Wisconsin average. Statewide, 78 of 202 UCMR5-tested systems have reported PFAS detections (38.6%). 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
718
Total Violations
83
Health-Based Violations
8
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
265
County
Grant
School/Daycare
No
MCL Violations
4
Monitoring Violations
73
Treatment Tech Violations
4

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 7 1997
Lead and Copper Rule MR 6 2024
Total Haloacetic Acids (HAA5) MR 5 2013
TTHM MR 5 2013
Gross Alpha, Excl. Radon and U MR 4 2018
Stage 1 Disinfectants and Disinfection Byproducts Rule TT 4 2024
Revised Total Coliform Rule MON 4 2018
Coliform (TCR) MCL 4 1996
DICHLOROMETHANE MR 2 1994
Vinyl chloride MR 2 1994
Carbon tetrachloride MR 2 1994
Trichloroethylene MR 2 1994
o-Dichlorobenzene MR 2 1994
trans-1,2-Dichloroethylene MR 2 1994
CHLOROBENZENE MR 2 1994
Ethylbenzene MR 2 1994
Styrene MR 2 1994
1,1-Dichloroethylene MR 2 1994
1,2-Dichloroethane MR 2 1994
1,1,1-Trichloroethane MR 2 1994
1,2-Dichloropropane MR 2 1994
Xylenes, Total MR 2 1994
Tetrachloroethylene MR 2 1994
1,2,4-Trichlorobenzene MR 2 1994
p-Dichlorobenzene MR 2 1994
Benzene MR 2 1994
1,1,2-Trichloroethane MR 2 1994
cis-1,2-Dichloroethylene MR 2 1994
Toluene MR 2 1994
Consumer Confidence Rule Other 1 2013

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 POTOSI 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 WI1220117 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 POTOSI 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 Lead and Copper Rule MR 6 SDWIS / WI1220117 / 5000
2024 Stage 1 Disinfectants and Disinfection Byproducts Rule TT 4 SDWIS / WI1220117 / 0400
2018 Gross Alpha, Excl. Radon and U MR 4 SDWIS / WI1220117 / 4000
2018 Revised Total Coliform Rule MON 4 SDWIS / WI1220117 / 8000
2013 Total Haloacetic Acids (HAA5) MR 5 SDWIS / WI1220117 / 2456
2013 TTHM MR 5 SDWIS / WI1220117 / 2950
2013 Consumer Confidence Rule Other 1 SDWIS / WI1220117 / 7000
1997 Coliform (TCR) MR 7 SDWIS / WI1220117 / 3100
1996 Coliform (TCR) MCL 4 SDWIS / WI1220117 / 3100
1994 DICHLOROMETHANE MR 2 SDWIS / WI1220117 / 2964
1994 Vinyl chloride MR 2 SDWIS / WI1220117 / 2976
1994 Carbon tetrachloride MR 2 SDWIS / WI1220117 / 2982
1994 Trichloroethylene MR 2 SDWIS / WI1220117 / 2984
1994 o-Dichlorobenzene MR 2 SDWIS / WI1220117 / 2968
1994 trans-1,2-Dichloroethylene MR 2 SDWIS / WI1220117 / 2979

How POTOSI WATERWORKS Compares

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

Metric POTOSI WATERWORKS Wisconsin avg Federal benchmark
Total violations 83 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 718 467 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
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is POTOSI WATERWORKS water safe to drink? ▼
POTOSI WATERWORKS (PWS ID: WI1220117) has 83 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 718 people using Groundwater sources.
How many people does POTOSI WATERWORKS serve? ▼
POTOSI WATERWORKS serves 718 people in POTOSI, Wisconsin. It is a Local-owned system using Groundwater water sources with 265 service connections.
What type of violations does POTOSI WATERWORKS have? ▼
POTOSI WATERWORKS has 83 total violations: 8 health-based violations (MCL exceedances or treatment failures), 73 monitoring/reporting violations, and 4 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in POTOSI WATERWORKS water? ▼
No PFAS testing data is available for POTOSI WATERWORKS under the EPA's UCMR5 monitoring program.
What water source does POTOSI WATERWORKS use? ▼
POTOSI 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.

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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.

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