PlainWater
States → Wisconsin

Non-Transient Non-Community Water System · PWS WI4360598

St Marys Sch

Cato, Wisconsin 54230 - drinking water served from groundwater sources to 226 people, tracked in EPA SDWIS and UCMR5.

226
People served
198
EPA violations
5
Health-based
Untested
UCMR5 result

The verdict

EPA records 198 drinking-water violations at St Marys Sch, 3% of them health-based - above the Wisconsin per-system average.

198
Total EPA violations on record
3%
Health-based (MCL / treatment failure)
226
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: St Marys Sch

St Marys Sch is a private-owned non-transient non-community water system that delivers drinking water to 226 residents in Cato, Wisconsin (Manitowoc County) through 1 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 198 total violations for this system , of which 5 (3%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 190 monitoring and reporting violations are on file. The most recent violation on record dates to 2008.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 8 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. Statewide, 78 of 202 UCMR5-tested systems have reported PFAS detections (38.6%).

St Marys Sch's 198 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
226
Total Violations
198
Health-Based Violations
5
Water Source
Groundwater

System Details

System Type
Non-Transient Non-Community
Owner Type
Private
Connections
1
County
Manitowoc
School/Daycare
Yes
MCL Violations
5
Monitoring Violations
190
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 8 1995
Coliform (TCR) MCL 5 2004
Lead and Copper Rule MR 4 2007
Nitrate MR 4 1997
Chromium MR 3 2001
Mercury MR 3 2001
Nickel MR 3 2001
Nitrite MR 3 2001
Selenium MR 3 2001
Thallium, Total MR 3 2001
Endrin MR 3 2001
BHC-GAMMA MR 3 2001
Dalapon MR 3 2001
Endothall MR 3 2001
Simazine MR 3 2001
Picloram MR 3 2001
Dinoseb MR 3 2001
Hexachlorocyclopentadiene MR 3 2001
Atrazine MR 3 2001
Heptachlor MR 3 2001
2,4-D MR 3 2001
HEXACHLOROBENZENE MR 3 2001
OXAMYL MR 3 2001
Xylenes, Total MR 3 2001
DICHLOROMETHANE MR 3 2001
o-Dichlorobenzene MR 3 2001
p-Dichlorobenzene MR 3 2001
Vinyl chloride MR 3 2001
Carbon tetrachloride MR 3 2001
1,2-Dichloropropane MR 3 2001

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 St Marys Sch.

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 WI4360598 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 St Marys Sch 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
2008 Public Notice Other 3 SDWIS / WI4360598 / 7500
2007 Lead and Copper Rule MR 4 SDWIS / WI4360598 / 5000
2004 Coliform (TCR) MCL 5 SDWIS / WI4360598 / 3100
2001 Chromium MR 3 SDWIS / WI4360598 / 1020
2001 Mercury MR 3 SDWIS / WI4360598 / 1035
2001 Nickel MR 3 SDWIS / WI4360598 / 1036
2001 Nitrite MR 3 SDWIS / WI4360598 / 1041
2001 Selenium MR 3 SDWIS / WI4360598 / 1045
2001 Thallium, Total MR 3 SDWIS / WI4360598 / 1085
2001 Endrin MR 3 SDWIS / WI4360598 / 2005
2001 BHC-GAMMA MR 3 SDWIS / WI4360598 / 2010
2001 Dalapon MR 3 SDWIS / WI4360598 / 2031
2001 Endothall MR 3 SDWIS / WI4360598 / 2033
2001 Simazine MR 3 SDWIS / WI4360598 / 2037
2001 Picloram MR 3 SDWIS / WI4360598 / 2040

How St Marys Sch Compares

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

Metric St Marys Sch Wisconsin avg Federal benchmark
Total violations 198 26 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 5 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 226 467 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 St Marys Sch water safe to drink? ▼
St Marys Sch (PWS ID: WI4360598) has 198 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 226 people using Groundwater sources.
How many people does St Marys Sch serve? ▼
St Marys Sch serves 226 people in Cato, Wisconsin. It is a Private-owned system using Groundwater water sources with 1 service connections.
What type of violations does St Marys Sch have? ▼
St Marys Sch has 198 total violations: 5 health-based violations (MCL exceedances or treatment failures), 190 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in St Marys Sch water? ▼
No PFAS testing data is available for St Marys Sch under the EPA's UCMR5 monitoring program.
What water source does St Marys Sch use? ▼
St Marys Sch uses Groundwater as its primary water source. It is classified as a Non-Transient Non-Community Water System, serving the same people for at least 6 months per year.
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.