Tap Water Quality Report
Tap water quality in Cincinnati, Ohio
Tap water in Cincinnati, Ohio receives a grade of D (67/100) from TapWaterSafety.org. It's served by CINCINNATI PUBLIC WATER SYSTEM. The most significant water quality concerns are: PFAS contamination; Total trihalomethanes (TTHMs) significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Bromodichloromethane significantly above health guideline; Arsenic detected. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in Cincinnati's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving Cincinnati.
PFAS contamination
Severe concernPerfluorooctane sulfonate (PFOS) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 38.1 ppb, 254x above the EWG health guideline of 0.15 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 11.6 ppb, 193x above the EWG health guideline of 0.06 ppb.
Bromodichloromethane significantly above health guideline
Moderate concernBromodichloromethane detected at 10.5 ppb, 175x above the EWG health guideline of 0.06 ppb.
Arsenic detected
Moderate concernArsenic detected at 0.233 ppb.
EPA compliance record
Official U.S. EPA records for CINCINNATI PUBLIC WATER SYSTEM (system ID OH3102612) 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 Cincinnati
Filters matched to the specific contaminants in Cincinnati'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 like TTHM. Look for NSF/ANSI 53 VOC or chloroform reduction.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
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 Cincinnati'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 |
|---|---|---|---|---|---|---|---|---|
| Total trihalomethanes (TTHMs) Disinfection byproduct |
38.1 ppb | 0.15 | 80.0 | 100 | — | — | — | 254× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
11.6 ppb | 0.06 | — | — | — | — | — | 193× over |
| Bromodichloromethane Disinfection byproduct |
10.5 ppb | 0.06 | — | — | — | — | — | 175× over |
| Dibromochloromethane Disinfection byproduct |
11.3 ppb | 0.1 | — | — | — | — | — | 113× over |
| Dibromoacetic acid Disinfection byproduct |
3.07 ppb | 0.03 | — | — | — | — | — | 102× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
8.17 ppb | 0.1 | 60.0 | 60 | — | — | — | 82× over |
| Arsenic Heavy metal |
0.233 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 58× over |
| Chloroform Disinfection byproduct |
11.2 ppb | 0.4 | — | — | — | — | — | 28× over |
| Dichloroacetic acid Disinfection byproduct |
2.87 ppb | 0.2 | — | — | — | — | — | 14× over |
| Bromoform Disinfection byproduct |
4.94 ppb | 0.5 | — | — | — | — | — | 9.9× over |
| Trichloroacetic acid Disinfection byproduct |
0.87 ppb | 0.1 | — | — | — | — | — | 8.7× over |
| Chromium (hexavalent) Heavy metal |
0.117 ppb | 0.02 | — | — | — | — | — | 5.9× over |
| Nitrate and nitrite Inorganic |
0.779 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 5.6× over |
| Nitrate Inorganic |
0.758 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 5.4× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.736 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 2.5× over |
| 1,4-Dioxane Semi-volatile organic compound |
0.401 ppb | 0.35 | — | — | 50 | 1 | — | 1.1× over |
| Chlorate Disinfection byproduct |
15.3 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
2.47 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
23.3 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
1.09 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.382 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Monobromoacetic acid Disinfection byproduct |
0.433 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
1.72 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.557 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.193 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.823 ppm | — | 4.0 | 1.5 | 1.5 | — | — | 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 CINCINNATI PUBLIC WATER SYSTEM.
General Contact
Treatment Plant
ZIP codes served
Cincinnati's public water systems serve the following ZIP codes: