Total trihalomethanes (TTHM) above the legal limit in the period starting January 2026.
Serves about 318 people (186 connections) with groundwater bought from Mercer County PWSD 1 and Princeton PWS.
From EPA's record for MO2010515. PurityMap is independent of Mercer PWS.
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11 health-based violations in the last 10 years, from EPA's SDWIS compliance database.
| Period | Contaminant | Measured | Legal limit | EPA status |
|---|---|---|---|---|
| Jan–Mar 2026 | Total trihalomethanes (TTHM) | 88 µg/L | 0.080 mg/L | Archived |
| Oct–Dec 2025 | Total trihalomethanes (TTHM) | 84 µg/L | 0.080 mg/L | Archived |
| Jul–Sep 2025 | Total trihalomethanes (TTHM) | 81.05 µg/L | 0.080 mg/L | Archived |
| Apr–Jun 2025 | Total trihalomethanes (TTHM) | 85 µg/L | 0.080 mg/L | Archived |
| Oct–Dec 2024 | Total trihalomethanes (TTHM) | 88 µg/L | 0.080 mg/L | Resolved |
| Period | Contaminant | Measured | Legal limit | EPA status |
|---|---|---|---|---|
| Jul–Sep 2024 | Total trihalomethanes (TTHM) | 97 µg/L | 0.080 mg/L | Resolved |
| Apr–Jun 2024 | Total trihalomethanes (TTHM) | 89.1 µg/L | 0.080 mg/L | Resolved |
| Oct–Dec 2020 | Total trihalomethanes (TTHM) | 85 µg/L | 0.080 mg/L | Resolved |
| Jul–Sep 2020 | Total trihalomethanes (TTHM) | 85 µg/L | 0.080 mg/L | Resolved |
| Apr–Jun 2020 | Total trihalomethanes (TTHM) | 83 µg/L | 0.080 mg/L | Resolved |
| Jul–Sep 2019 | Total trihalomethanes (TTHM) | 83 µg/L | 0.080 mg/L | Resolved |
No lab results for other contaminants (like PFAS) are on file for this system. EPA required that testing from systems serving more than 3,300 people, plus a sample of smaller ones.
Screening tells you if something is worth a closer look; a lab result is the number you can act on.
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Screening: quick check, not lab-grade
Safe Home (EnviroTestKits)
Lead, read as one of three ranges: 0–4, 5–15 or 15+ ppb
Turnaround: 5 minutes
What it can't tell you: It shows a lead range, not an exact level, and tests nothing else unless you pay extra for the optional lab test.
Lab-certified results
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638 · 2–4 business days after the lab receives it
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Get PurityMap updates about this water system.
Follow this water →Mercer PWS's phone number on EPA record is 660-382-4210. Its mailing address is 14402 STATE ST, PO BOX 457, MERCER, MO 64661-0000.
According to EPA's record, Mercer PWS uses groundwater bought from Mercer County PWSD 1 and Princeton PWS.
EPA's record shows 11 health-based violations for Mercer PWS in the 10 years to July 9, 2026. Total trihalomethanes (TTHM) were above the legal limit in the period starting January 2026. EPA also lists 5 missed or late tests or reports in 10 years. The record comes from EPA's SDWIS compliance database.
The 90th-percentile lead result in Mercer PWS's latest lead and copper round, which ended in December 2025, was 13.66 µg/L, below the federal action level of 15 µg/L.
PurityMap has no verified website for Mercer PWS. Its phone number on EPA record is 660-382-4210. Its mailing address on EPA record is 14402 STATE ST, PO BOX 457, MERCER, MO 64661-0000. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.