Knox County Water Quality

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

Knox County, Illinois: 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 Knox 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.

Perfluorooctanoic acid (PFOA)GALESBURG4.0 ng/L federal MCL (2024) · US EPA14 ng/L

GALESBURG14 ng/LSample date: 2023-02-27 to 2023-08-24

Perfluorooctanesulfonic acid (PFOS)GALESBURG4.0 ng/L federal MCL (2024) · US EPA4.2 ng/L

GALESBURG4.2 ng/LSample date: 2023-02-27 to 2023-08-24

Perfluorobutanesulfonic acid (PFBS)GALESBURG2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPA6.6 ng/L

GALESBURG6.6 ng/LSample date: 2023-02-27 to 2023-08-24

Perfluorobutanoic acid (PFBA)GALESBURGNo federal or state limit; shown for transparency85 ng/L

GALESBURG85 ng/LSample date: 2023-02-27 to 2023-08-24

Perfluoropentanoic acid (PFPeA)GALESBURGNo federal or state limit; shown for transparency15 ng/L

GALESBURG15 ng/LSample date: 2023-02-27 to 2023-08-24

26 substances tested, none detected in this systemShow

Tested in this system: GALESBURG

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)
Lead (90th percentile)
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)
Perfluorodecanoic acid (PFDA)
Perfluorododecanoic acid (PFDoA)
Perfluoroheptanesulfonic acid (PFHpS)
Perfluoroheptanoic acid (PFHpA)
Perfluorohexanesulfonic acid (PFHxS)
Perfluorohexanoic acid (PFHxA)
Perfluorononanoic acid (PFNA)
Perfluoropentanesulfonic acid (PFPeS)
Perfluorotetradecanoic acid (PFTA)
Perfluorotridecanoic acid (PFTrDA)
Perfluoroundecanoic acid (PFUnA)

1 city

Cities ranked by the records

1
GalesburgGALESBURG
PFAS sample above a limit
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 Knox County1 of 1 city report had a PFAS sample above a 2024 EPA limit

Galesburg4.2 ng/L

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

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 Illinois

Who supplies the county

Largest water systems

GalesburgGALESBURG · IL0950200
31,620 served

Questions

Frequently asked

How does Knox County tap water compare across cities?

PurityMap ranks 1 city in Knox 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 Galesburg's main water system: GALESBURG · PWSID IL0950200 · Purity Score 57 (Fair) · 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 Knox County cities had a PFAS sample above a 2024 EPA limit?

1 of 1 Knox County city report had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Galesburg (PFOA 14 ng/L). That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation. PFAS were detected at any level in 1.

Is there lead in Knox County tap water?

Utilities report lead as a 90th-percentile result from home taps. 0 of 1 Knox 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.

Next step

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