Ohio Water Report Card: Worst Water Systems
The most contaminated public water systems in Ohio, ranked by PFAS levels, lead, and EPA violations from official EPA data.
Quick Answer
Newton Falls City has the highest PFAS in Ohio at 220 ppt (55x the EPA limit). Dayton Public Water System has the highest lead at 470 ppb. The tables below rank the worst systems in each category so you can see how your water compares.
Highest PFAS Levels in Ohio
Public water systems in Ohio with the highest peak PFAS ("forever chemical") reading in EPA UCMR5 testing (2023-2025). The EPA enforceable limit for PFOA and PFOS is 4 ppt.
| # | Water System | Location | Peak PFAS (ppt) | Compounds | vs 4 ppt limit |
|---|---|---|---|---|---|
| 1 | Newton Falls City | Newton Falls · 6,109 served | 220 | 6 | 55x |
| 2 | Ottawa Village | Ottawa · 4,393 served | 90.4 | 4 | 23x |
| 3 | Bluffton Village | Bluffton · 4,125 served | 42 | 4 | 11x |
| 4 | Kings Island Pws | – | 28.9 | 4 | 7x |
| 5 | Wright-Patterson Afb Area A Pws | Vandalia · 16,551 served | 25 | 6 | 6x |
| 6 | Sanitary District #4 | Columbus · 8,575 served | 22 | 6 | 6x |
| 7 | Mcdonald Village Pws | Mcdonald · 3,172 served | 21.2 | 2 | 5x |
| 8 | Belpre City Pws | Belpre · 6,441 served | 21 | 2 | 5x |
| 9 | Wellston City Pws | Wellston · 7,000 served | 20.2 | 3 | 5x |
| 10 | Zanesville Pws | Zanesville · 29,381 served | 20.1 | 1 | 5x |
| 11 | Girard City Pws | Girard · 14,122 served | 20.1 | 3 | 5x |
| 12 | Warren Comm W And S Assn 2 | Marietta · 7,215 served | 20 | 2 | 5x |
Highest Lead Levels in Ohio
Community water systems in Ohio with the highest 90th-percentile lead result under the EPA Lead and Copper Rule. The EPA action level is 15 ppb; there is no safe level of lead for children.
| # | Water System | Location | Lead 90th-pctile (ppb) | vs 15 ppb |
|---|---|---|---|---|
| 1 | Dayton Public Water System | Dayton · 141,407 served | 470 | 31.3x over |
| 2 | Tuscarawas Village | Tuscarawas · 1,056 served | 156 | 10.4x over |
| 3 | Wright State University | Dayton · 8,948 served | 20.3 | 1.4x over |
| 4 | Pemberville Village Pws | Pemberville · 1,326 served | 19.9 | 1.3x over |
| 5 | Wellington Village Pws | Wellington · 4,802 served | 17 | 1.1x over |
| 6 | Leetonia Village Pws | New Waterford · 1,833 served | 16.4 | 1.1x over |
| 7 | New Paris Village Pws | New Paris · 1,681 served | 15.6 | 1.0x over |
| 8 | Bellbrook Water Works | Bellbrook · 9,475 served | 15.1 | 1.0x over |
| 9 | Mid-Ohio Wsd Plain City Wtp | Columbus · 4,467 served | 14.3 | within |
| 10 | Belpre City Pws | Belpre · 6,441 served | 14 | within |
| 11 | Aqua Ohio - Lake White Pws | Westerville · 1,229 served | 14 | within |
| 12 | Apple Creek Village Pws | Lakeville · 1,190 served | 14 | within |
Most EPA Violations in Ohio
Community water systems in Ohio with the most health-based EPA Safe Drinking Water Act violations on record. A health-based violation means a contaminant exceeded its federal limit or required treatment was not applied.
| # | Water System | Location | Health-based violations |
|---|---|---|---|
| 1 | Maysville Regional Water | White Cottage · 6,540 served | 39 |
| 2 | Defiance City | Defiance · 16,494 served | 22 |
| 3 | Ayersville Water And Sewer District | Defiance · 2,372 served | 21 |
| 4 | Byesville | Byesville · 5,104 served | 16 |
| 5 | Green Springs Village Pws | Green Springs · 1,592 served | 16 |
| 6 | Nelsonville Pws | Nelsonville · 6,656 served | 15 |
| 7 | Holgate Village | Holgate · 1,150 served | 13 |
| 8 | Archbold Village | Archbold · 5,586 served | 13 |
| 9 | Bluffton Village | Bluffton · 4,125 served | 10 |
| 10 | New Lexington | New Lexington · 5,161 served | 9 |
| 11 | Northwestern W And Sd - Oregon Wtln 200 | Bowling Green · 9,629 served | 9 |
| 12 | Wauseon City Pws | Wauseon · 7,568 served | 8 |
How This Report Card Is Built
PFAS rankings use EPA UCMR5 monitoring (2023-2025), showing each system's peak detection above the 4 ppt EPA limit. Lead rankings use the EPA Lead and Copper Rule 90th-percentile tap results. Violation counts come from the EPA Safe Drinking Water Information System (SDWIS) and count health-based violations. Lead and violation lists are limited to community water systems serving 1,000 or more people. Figures are the most severe on record and do not necessarily reflect current treated water.
Frequently Asked Questions
What is the most PFAS-contaminated water system in Ohio?
In EPA UCMR5 testing (2023-2025), Newton Falls City in Newton Falls had the highest recorded PFAS level in Ohio at 220 ppt - about 55x the EPA's 4 ppt limit for PFOA and PFOS.
Which Ohio water system has the highest lead levels?
Dayton Public Water System in Dayton had the highest 90th-percentile lead result in Ohio under the EPA Lead and Copper Rule at 470 ppb - 31.3x the 15 ppb action level.
Which Ohio water system has the most EPA violations?
Maysville Regional Water in White Cottage has the most health-based EPA Safe Drinking Water Act violations on record in Ohio, with 39 violations.
Where does the Ohio water report card data come from?
PFAS figures come from EPA UCMR5 monitoring (2023-2025), lead from the EPA Lead and Copper Rule 90th-percentile tap results, and violations from EPA SDWIS health-based violation records. Figures are the most severe on record and do not necessarily reflect current treated water. Check your exact address at knowyourexposure.com.
What Ohio Residents Should Do
- Look up your exact address at knowyourexposure.com for your system's data
- See the full Ohio water quality overview
- If your system is listed, a certified filter (reverse osmosis for PFAS, NSF-53 for lead) reduces exposure at the tap. See the best water filters.