Jefferson County Water Quality

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

Jefferson County, Kentucky: 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

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)LOUISVILLE WATER COMPANY4.0 ng/L federal MCL (2024) · US EPA7.5 ng/L

LOUISVILLE WATER COMPANY7.5 ng/LSample date: 2023-02-15 to 2023-11-15

Lead (90th percentile)LOUISVILLE WATER COMPANY15 µg/L federal action level · US EPA1.1 µg/L

LOUISVILLE WATER COMPANY1.1 µg/LMonitoring period: 2021–2023

Perfluorobutanesulfonic acid (PFBS)LOUISVILLE WATER COMPANY2,000 ng/L EPA health advisory (screening, not a legal limit) · US EPA3 ng/L

LOUISVILLE WATER COMPANY3 ng/LSample date: 2023-02-15 to 2023-11-15

Perfluorohexanoic acid (PFHxA)LOUISVILLE WATER COMPANY400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLE3.6 ng/L

LOUISVILLE WATER COMPANY3.6 ng/LSample date: 2023-02-15 to 2023-11-15

Perfluoropentanoic acid (PFPeA)LOUISVILLE WATER COMPANYNo federal or state limit; shown for transparency4.1 ng/L

LOUISVILLE WATER COMPANY4.1 ng/LSample date: 2023-02-15 to 2023-11-15

26 substances tested, none detected in this systemShow

Tested in this system: LOUISVILLE WATER COMPANY

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)
Perfluorobutanoic acid (PFBA)
Perfluorodecanoic acid (PFDA)
Perfluorododecanoic acid (PFDoA)
Perfluoroheptanesulfonic acid (PFHpS)
Perfluoroheptanoic acid (PFHpA)
Perfluorohexanesulfonic acid (PFHxS)
Perfluorononanoic acid (PFNA)
Perfluorooctanesulfonic acid (PFOS)
Perfluoropentanesulfonic acid (PFPeS)
Perfluorotetradecanoic acid (PFTA)
Perfluorotridecanoic acid (PFTrDA)
Perfluoroundecanoic acid (PFUnA)

1 city

Cities ranked by the records

1
LouisvilleLOUISVILLE WATER COMPANY
PFAS above 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 Jefferson County1 of 1 city reports a regulated PFAS above the federal limit

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

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 Kentucky

Who supplies the county

Largest water systems

LouisvilleLOUISVILLE WATER COMPANY · KY0560258
806,997 served

Questions

Frequently asked

How does Jefferson County tap water compare across cities?

PurityMap ranks 1 city in Jefferson 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 Louisville's main water system: LOUISVILLE WATER COMPANY · PWSID KY0560258 · Purity Score 58 (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 Jefferson County cities have PFAS above the federal limit?

1 city of 1 had at least one regulated PFAS (PFOA, PFOS or PFHxS) measured above the 2024 federal limit in EPA's UCMR 5 testing, including Louisville (PFOA 7.5 ng/L). PFAS were detected at any level in 1.

Is there lead in Jefferson County tap water?

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

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