Ohio Water Quality Report
Tap water quality data for 11 cities in Ohio, updated 2026.
US average: 100 ppm
7 of 11 cities violation-free
11 cities tested
11 water systems tracked
Cleanest Tap Water in Ohio
Cities with the fewest water quality issues
Columbus
1.3M served
Cincinnati
750K served
Akron City Pws
280K served
Del-co
150K served
Dayton
141K served
Youngstown City Pws
131K served
Canton
107K served
Cleveland
1.3M served
Clermont
133K served
Butler Co.
117K served
Most Water Quality Issues in Ohio
Cities with the most violations and concerns
Water Hardness Across Ohio
Not sure what your hardness means? Use our Water Hardness Calculator or find the best hardness test kits.
Ohio Tap Water: What You Need to Know
Ohio has 11 tracked water utilities serving approximately 4.8M residents. The average water hardness is 243 ppm (14.2 GPG), classified as Very Hard — above the national average of 100 ppm. Hardness ranges from 163.5 ppm in Youngstown City Pws to 309 ppm in Butler Co..
In the past 3 years, 4 of 11 cities in Ohio have recorded water quality violations, totaling 16 violations (4 health-based). All 11 tested cities have lead levels below the EPA action level of 15 ppb.
With very hard water on average, many Ohio residents may notice mineral buildup on fixtures, dry skin, or stiff-feeling hair. A shower filter for hard water can help reduce chlorine exposure, while a water softener addresses the mineral buildup directly.
Frequently Asked Questions About Ohio Water
Is tap water safe to drink in Ohio?
Most tap water in Ohio meets EPA standards, but 4 cities have recorded violations in the past 3 years (4 health-based). We recommend checking your specific city's report on TapWater.org and considering a home water test.
How hard is the water in Ohio?
Ohio's average water hardness is 243 ppm (14.2 GPG), classified as Very Hard. This is above the national average of 100 ppm. Hardness varies significantly by city — use our Water Hardness Calculator to check your specific area.
Which city in Ohio has the cleanest tap water?
Based on EPA violation data, lead testing, and water quality metrics, Columbus ranks as having the cleanest tap water in Ohio. It has zero violations in the past 3 years and lead levels well below the EPA action level.
Which city in Ohio has the most water quality issues?
Toledo City of currently has the most water quality concerns in Ohio, with 4 violations in the past 3 years. Residents should check their city's detailed water quality report and consider using a certified water filter.
Where does Ohio get its water from?
The majority of Ohio's water systems (91%) use surface water as their primary source. Surface water comes from rivers, lakes, and reservoirs. Each city's specific source can vary — check individual city reports for details.
All 11 Cities
Sorted by population served
Cleveland
Utility serves 1.3M
Columbus
Utility serves 1.3M
Cincinnati
Utility serves 750K
Toledo City of
Utility serves 360K
Akron City Pws
Utility serves 280K
Del-co
Utility serves 150K
Dayton
Utility serves 141K
Clermont
Utility serves 133K
Youngstown City Pws
Utility serves 131K
Butler Co.
Utility serves 117K
Canton
Utility serves 107K