Is Tap Water Safe to Drink in Cincinnati?
Yes, tap water in Cincinnati is safe to drink and is frequently cited among the best-treated in the nation. Greater Cincinnati Water Works pioneered large-scale granular activated carbon treatment on the Ohio River and added UV disinfection.
Water Source
Greater Cincinnati Water Works draws mainly from the Ohio River at the Richard Miller Treatment Plant — famous for its massive granular activated carbon (GAC) contactors and, since 2013, one of the largest UV disinfection installations in North America — plus groundwater treated at the Bolton plant.
EPA Compliance Status
Meets all federal Safe Drinking Water Act standards. The GAC-plus-UV treatment train removes trace organics and pathogens beyond conventional requirements, and the utility is a frequent national benchmark for river-source treatment.
Notable Contaminants & Context
- •The Ohio River carries upstream industrial and agricultural inputs — the reason Cincinnati invested in carbon treatment decades ago; GAC strips trace organics including many PFAS compounds
- •Spill events upstream (like the 2023 East Palestine plume concerns) are managed with real-time monitoring and intake shutdowns
- •Disinfection byproducts are kept low partly because carbon removes their precursors
- •Legacy lead service lines in older neighborhoods are inventoried and being replaced
Water Quality Data
Key contaminants detected vs. regulatory limits. All values from the most recent published report — Source: Greater Cincinnati Water Works 2024 CCR.
| Contaminant | Detected | Limit | Status |
|---|---|---|---|
| Chlorine (total) | 1.9 mg/L | 4.0 mg/L | ✓ |
| Fluoride | 0.71 mg/L | 4.0 mg/L | ✓ |
| Lead (90th percentile) | 3.6 µg/L | 15.0 µg/L | ✓ |
| Nitrate (as N) | 1.8 mg/L | 10.0 mg/L | ✓ |
| TTHM (Total Trihalomethanes) | 42.3 µg/L | 80.0 µg/L | ✓ |
| HAA5 (Haloacetic Acids) | 31.6 µg/L | 60.0 µg/L | ✓ |
✓ = below limit ⚠ = above health goal ✗ = exceeds guideline
How It Compares
Cincinnati is the reference case for treating a hard-working industrial river to a very high standard — its carbon-and-UV plant outperforms conventional treatment found in most river cities and positioned it well for the EPA's new PFAS rules.
Tips
- •Cincinnati's water is excellent from the tap; no filter is needed for safety
- •The utility offers lead service line lookups and replacement scheduling for older homes
- •Annual reports detail GAC and UV performance
Frequently Asked Questions
Sources & References
The safety rating and guidance on this page draw on the following sources. See our full methodology.
- •US EPA Safe Drinking Water Act regulations
- •EWG Tap Water Database
- •The utility's most recent Consumer Confidence Report (CCR)
- •WHO Guidelines for Drinking-water Quality