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Community Water System · PWS MO6010659

Potosi PWS

Potosi, Missouri 63664-0000 - drinking water served from groundwater sources to 2,527 people, tracked in EPA SDWIS and UCMR5.

2,527
People served
468
EPA violations
414
Health-based
Untested
UCMR5 result

The verdict

EPA records 468 drinking-water violations at Potosi PWS, 88% of them health-based - above the Missouri per-system average.

468
Total EPA violations on record
88%
Health-based (MCL / treatment failure)
2,527
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Potosi PWS

Potosi PWS is a local-owned community water system that delivers drinking water to 2,527 residents in Potosi, Missouri (Washington County) through 1,236 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 468 total violations for this system , of which 414 (88%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 27 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 185 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 Missouri, EPA tracks 2,823 public water systems serving 5,855,885 people, with 201,695 cumulative violations and 54,821 health-based violations on record. About 95% of systems in the state carry at least one violation, and state-wide the average per system is 71.4 violations. Statewide, 162 of 230 UCMR5-tested systems have reported PFAS detections (70.4%).

Potosi PWS's 468 violations sit above the Missouri 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
2,527
Total Violations
468
Health-Based Violations
414
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Local
Connections
1,236
County
Washington
School/Daycare
No
MCL Violations
414
Monitoring Violations
27
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MCL 185 2015
Combined Radium (-226 and -228) MCL 122 2007
Gross Alpha, Excl. Radon and U MCL 107 2007
Coliform (TCR) MR 13 2002
Public Notice Other 7 2024
Revised Total Coliform Rule MON 4 2023
E. COLI MR 4 2010
Gross Alpha, Excl. Radon and U MR 3 2007
Combined Radium (-226 and -228) MR 3 2007

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 PWS.

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 MO6010659 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Missouri Drinking Water Authority

Missouri DNR, Public Drinking Water Branch is the primacy agency that licenses and inspects Potosi PWS under EPA-delegated authority.

Open MO regulator portal

Source: Missouri DNR, Public Drinking Water Branch

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 7 SDWIS / MO6010659 / 7500
2023 Revised Total Coliform Rule MON 4 SDWIS / MO6010659 / 8000
2015 Coliform (TCR) MCL 185 SDWIS / MO6010659 / 3100
2010 E. COLI MR 4 SDWIS / MO6010659 / 3014
2007 Combined Radium (-226 and -228) MCL 122 SDWIS / MO6010659 / 4010
2007 Gross Alpha, Excl. Radon and U MCL 107 SDWIS / MO6010659 / 4000
2007 Gross Alpha, Excl. Radon and U MR 3 SDWIS / MO6010659 / 4000
2007 Combined Radium (-226 and -228) MR 3 SDWIS / MO6010659 / 4010
2002 Coliform (TCR) MR 13 SDWIS / MO6010659 / 3100

How Potosi PWS Compares

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

Metric Potosi PWS Missouri avg Federal benchmark
Total violations 468 71.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 414 19.4 Indicates a contaminant exceeded a federal MCL
PFAS detection None 70.4% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 2,527 2,074 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,823 regulated public water systems in Missouri.

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 Potosi PWS water safe to drink? ▼
Potosi PWS (PWS ID: MO6010659) has 468 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 2,527 people using Groundwater sources.
How many people does Potosi PWS serve? ▼
Potosi PWS serves 2,527 people in Potosi, Missouri. It is a Local-owned system using Groundwater water sources with 1,236 service connections.
What type of violations does Potosi PWS have? ▼
Potosi PWS has 468 total violations: 414 health-based violations (MCL exceedances or treatment failures), 27 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Potosi PWS water? ▼
No PFAS testing data is available for Potosi PWS under the EPA's UCMR5 monitoring program.
What water source does Potosi PWS use? ▼
Potosi PWS 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.