St. Francois County Water Quality

Name: St. Francois County Water Quality Data (2026)
Creator: PurityMap
License: https://creativecommons.org/licenses/by/4.0/

St. Francois County, Missouri: one city report built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.

Find my system Open on the map Private wells in St. Francois County

Across the county's systems

Highest result for each contaminant

One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.

Perfluorohexanesulfonic acid (PFHxS)FARMINGTON PWS10 ng/L federal MCL (2024) · US EPA4.8 ng/L

FARMINGTON PWS4.8 ng/LSample date: 2024-06-14 to 2025-03-03

Lead (90th percentile)FARMINGTON PWS15 µg/L federal action level · US EPA4.82 µg/L

FARMINGTON PWS4.82 µg/LMonitoring period: 2022–2024

Perfluoropentanoic acid (PFPeA)FARMINGTON PWSNo federal or state limit; shown for transparency3.8 ng/L

FARMINGTON PWS3.8 ng/LSample date: 2024-06-14 to 2025-03-03

28 substances tested, none detected in this systemShow

Tested in this system: FARMINGTON PWS

11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
Lithium
N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
Perfluoro-3-methoxypropanoic acid (PFMPA)
Perfluoro-4-methoxybutanoic acid (PFMBA)
Perfluorobutanesulfonic acid (PFBS)
Perfluorobutanoic acid (PFBA)
Perfluorodecanoic acid (PFDA)
Perfluorododecanoic acid (PFDoA)
Perfluoroheptanesulfonic acid (PFHpS)
Perfluoroheptanoic acid (PFHpA)
Perfluorohexanoic acid (PFHxA)
Perfluorononanoic acid (PFNA)
Perfluorooctanesulfonic acid (PFOS)
Perfluorooctanoic acid (PFOA)
Perfluoropentanesulfonic acid (PFPeS)
Perfluorotetradecanoic acid (PFTA)
Perfluorotridecanoic acid (PFTrDA)
Perfluoroundecanoic acid (PFUnA)

1 city

Cities ranked by the records

1
FarmingtonFARMINGTON PWS
PFAS detected, within limitLead below action level
Open city report →

Showing 1 of 1 cities · scores are system-level, not tap tests

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.

PFAS in St. Francois CountyPFAS detected in 1 of 1 city; none had a sample above a 2024 EPA limit

4.0 ng/L federal MCL · PFOS, ng/LPFAS in Missouri

Lead

0of 1 city above the 15 µg/L action level

Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.

Lead in Missouri

Who supplies the county

Largest water systems

FarmingtonFARMINGTON PWS · MO4010270
18,217 served

Questions

Frequently asked

How does St. Francois County tap water compare across cities?

PurityMap ranks 1 city in St. Francois County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Farmington's main water system: FARMINGTON PWS · PWSID MO4010270 · Purity Score 83 (Good) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many St. Francois County cities had a PFAS sample above a 2024 EPA limit?

None of the 1 St. Francois County city report had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing. PFAS were detected below the limit in 1.

Is there lead in St. Francois County tap water?

Utilities report lead as a 90th-percentile result from home taps. 1 of 1 St. Francois County cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

Have St. Francois County water systems had drinking-water violations?

1 city in St. Francois County has a health-based violation in the federal SDWIS record within about the last ten years. Each city report lists the contaminant, year and whether it was resolved.

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