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Community Water System · PWS MO2036165

Lake Thunderhead

Unionville, Missouri 63565-0000 - drinking water served from surface water sources to 585 people, tracked in EPA SDWIS and UCMR5.

585
People served
93
EPA violations
40
Health-based
Untested
UCMR5 result

The verdict

EPA records 93 drinking-water violations at Lake Thunderhead, 43% of them health-based - above the Missouri per-system average.

93
Total EPA violations on record
43%
Health-based (MCL / treatment failure)
585
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Lake Thunderhead

Lake Thunderhead is a private-owned community water system that delivers drinking water to 585 residents in Unionville, Missouri (Putnam County) through 652 service connections. Its water is drawn from surface water sources. EPA's Safe Drinking Water Information System records 93 total violations for this system , of which 40 (43%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 43 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 Revised Total Coliform Rule, recorded in 30 violations (MON). 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%).

Lake Thunderhead's 93 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
585
Total Violations
93
Health-Based Violations
40
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Private
Connections
652
County
Putnam
School/Daycare
No
MCL Violations
40
Monitoring Violations
43
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Revised Total Coliform Rule MON 30 2021
TTHM MCL 20 2016
Total Haloacetic Acids (HAA5) MCL 20 2016
Consumer Confidence Rule Other 6 2024
Coliform (TCR) MR 4 2013
TTHM MR 4 2019
Total Haloacetic Acids (HAA5) MR 4 2019
Public Notice Other 2 2017
Lead and Copper Rule MR 1 2004

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 Lake Thunderhead.

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 MO2036165 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 Lake Thunderhead 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 Consumer Confidence Rule Other 6 SDWIS / MO2036165 / 7000
2021 Revised Total Coliform Rule MON 30 SDWIS / MO2036165 / 8000
2019 TTHM MR 4 SDWIS / MO2036165 / 2950
2019 Total Haloacetic Acids (HAA5) MR 4 SDWIS / MO2036165 / 2456
2017 Public Notice Other 2 SDWIS / MO2036165 / 7500
2016 TTHM MCL 20 SDWIS / MO2036165 / 2950
2016 Total Haloacetic Acids (HAA5) MCL 20 SDWIS / MO2036165 / 2456
2013 Coliform (TCR) MR 4 SDWIS / MO2036165 / 3100
2004 Lead and Copper Rule MR 1 SDWIS / MO2036165 / 5000

How Lake Thunderhead Compares

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

Metric Lake Thunderhead Missouri avg Federal benchmark
Total violations 93 71.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 40 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 585 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 Lake Thunderhead water safe to drink? ▼
Lake Thunderhead (PWS ID: MO2036165) has 93 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 585 people using Surface Water sources.
How many people does Lake Thunderhead serve? ▼
Lake Thunderhead serves 585 people in Unionville, Missouri. It is a Private-owned system using Surface Water water sources with 652 service connections.
What type of violations does Lake Thunderhead have? ▼
Lake Thunderhead has 93 total violations: 40 health-based violations (MCL exceedances or treatment failures), 43 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Lake Thunderhead water? ▼
No PFAS testing data is available for Lake Thunderhead under the EPA's UCMR5 monitoring program.
What water source does Lake Thunderhead use? ▼
Lake Thunderhead uses Surface Water 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.