Tap Water Quality Report
Tap water quality in Louisville, Kentucky
Tap water in Louisville, Kentucky receives a grade of C (74/100) from TapWaterSafety.org. It's served by LOUISVILLE WATER COMPANY. The most significant water quality concerns are: PFAS contamination; Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in Louisville's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving Louisville.
PFAS contamination
Severe concernPerfluorooctanoic acid (PFOA), Perfluorooctane sulfonate (PFOS) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 27.5 ppb, 459x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 23.8 ppb, 159x above the EWG health guideline of 0.15 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 15.8 ppb, 158x above the EWG health guideline of 0.1 ppb.
EPA compliance record
Official U.S. EPA records for LOUISVILLE WATER COMPANY (system ID KY0560258) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for Louisville
Filters matched to the specific contaminants in Louisville's water supply.
Filter certified for PFOA/PFOS (NSF/ANSI 53 or 58)
$180-$750Reverse osmosis and some carbon block filters reduce PFAS. Look for certification to NSF/ANSI 53 or 58 for PFOA/PFOS.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in Louisville's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
27.5 ppb | 0.06 | — | — | — | — | — | 459× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
23.8 ppb | 0.15 | 80.0 | 100 | — | — | — | 159× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
15.8 ppb | 0.1 | 60.0 | 60 | — | — | — | 158× over |
| Perfluorooctanoic acid (PFOA) PFAS |
1.82 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 20× over |
| Nitrate Inorganic |
0.577 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 4.1× over |
| Nitrate and nitrite Inorganic |
0.578 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 4.1× over |
| Chromium (hexavalent) Heavy metal |
0.0806 ppb | 0.02 | — | — | — | — | — | 4.0× over |
| Chlorite Disinfection byproduct |
141.7 ppb | 50.0 | 1000.0 | — | — | — | — | 2.8× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.361 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 1.2× over |
| 1,4-Dioxane Semi-volatile organic compound |
0.22 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Chlorate Disinfection byproduct |
72.5 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) Other |
1.22 ppt | 9.0 | 10.0 | — | — | — | — | Below guideline |
| Molybdenum Other |
2.31 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Atrazine Pesticide/Herbicide |
0.004 ppb | 0.1 | 3.0 | 0.1 | 100 | 0.15 | — | Below guideline |
| Aluminum Heavy metal |
22.8 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Barium Heavy metal |
12.8 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Manganese Heavy metal |
1.11 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Vanadium Other |
0.125 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Perfluoropentanoic Acid (PFPeA) PFAS |
1.33 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| 2,4-D Pesticide/Herbicide |
0.0242 ppb | 20.0 | 70.0 | — | — | — | — | Below guideline |
| Perfluorohexanoic Acid (PFHxA) PFAS |
1.17 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.375 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.162 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Ethinyl estradiol Other |
0.138 ppt | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.661 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Nitrite Inorganic |
0.0015 ppm | — | 1.0 | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from LOUISVILLE WATER COMPANY.
General Contact
Treatment Plant
ZIP codes served
Louisville's public water systems serve the following ZIP codes: