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Community Water System · PWS IL1671250

Thayer

Thayer, Illinois 62689 - drinking water served from surface water sources to 721 people, tracked in EPA SDWIS and UCMR5.

721
People served
93
EPA violations
23
Health-based
Untested
UCMR5 result

The verdict

EPA records 93 drinking-water violations at Thayer, 25% of them health-based - above the Illinois per-system average.

93
Total EPA violations on record
25%
Health-based (MCL / treatment failure)
721
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Thayer

Thayer is a local-owned community water system that delivers drinking water to 721 residents in Thayer, Illinois (Sangamon County) through 364 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 23 (25%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 45 monitoring and reporting violations are on file. The most recent violation on record dates to 2023.

The most frequently cited contaminant at this system is Atrazine, recorded in 18 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 Illinois, EPA tracks 5,117 public water systems serving 12,576,876 people, with 355,322 cumulative violations and 52,932 health-based violations on record. About 81% of systems in the state carry at least one violation, and state-wide the average per system is 69.4 violations. Statewide, 199 of 487 UCMR5-tested systems have reported PFAS detections (40.9%).

Thayer's 93 violations sit above the Illinois 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
721
Total Violations
93
Health-Based Violations
23
Water Source
Surface Water

System Details

System Type
Community
Owner Type
Local
Connections
364
County
Sangamon
School/Daycare
No
MCL Violations
18
Monitoring Violations
45
Treatment Tech Violations
5

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Atrazine MCL 18 1994
Coliform (TCR) MR 13 2013
Lead and Copper Rule MR 12 2023
Consumer Confidence Rule Other 8 2019
Total Haloacetic Acids (HAA5) MR 8 2019
Chloramine MR 6 2013
TTHM MR 6 2019
Interim Enhanced Surface Water Treatment Rule TT 5 2010

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 Thayer.

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 IL1671250 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Illinois Drinking Water Authority

Illinois EPA, Bureau of Water is the primacy agency that licenses and inspects Thayer under EPA-delegated authority.

Open IL regulator portal

Source: Illinois EPA, Bureau of Water

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
2023 Lead and Copper Rule MR 12 SDWIS / IL1671250 / 5000
2019 Consumer Confidence Rule Other 8 SDWIS / IL1671250 / 7000
2019 Total Haloacetic Acids (HAA5) MR 8 SDWIS / IL1671250 / 2456
2019 TTHM MR 6 SDWIS / IL1671250 / 2950
2013 Coliform (TCR) MR 13 SDWIS / IL1671250 / 3100
2013 Chloramine MR 6 SDWIS / IL1671250 / 1006
2010 Interim Enhanced Surface Water Treatment Rule TT 5 SDWIS / IL1671250 / 0300
1994 Atrazine MCL 18 SDWIS / IL1671250 / 2050

How Thayer Compares

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

Metric Thayer Illinois avg Federal benchmark
Total violations 93 69.4 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 23 10.3 Indicates a contaminant exceeded a federal MCL
PFAS detection None 40.9% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 721 2,458 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 5,117 regulated public water systems in Illinois.

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 Thayer water safe to drink? ▼
Thayer (PWS ID: IL1671250) has 93 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 721 people using Surface Water sources.
How many people does Thayer serve? ▼
Thayer serves 721 people in Thayer, Illinois. It is a Local-owned system using Surface Water water sources with 364 service connections.
What type of violations does Thayer have? ▼
Thayer has 93 total violations: 23 health-based violations (MCL exceedances or treatment failures), 45 monitoring/reporting violations, and 5 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Thayer water? ▼
No PFAS testing data is available for Thayer under the EPA's UCMR5 monitoring program.
What water source does Thayer use? ▼
Thayer 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.