Ohio Drinking Water Compliance Records
1,125 water systems serving 10,455,183 people. 32,404 historical EPA violation records in the Q2 2026 snapshot.
TapScore Compliance-History Grades
A
439
39%
B
327
29%
C
253
22%
D
95
8%
F
11
1%
1,125
Water Systems
10,455,183
Population Served
32,404
Historical Records
3,918
Health-Based (All Years)
Systems With the Most Recent EPA Records
RICHWOOD VILLAGE PWS
2,200 served41 historical records32 recent
D
CONTINENTAL VILLAGE PWS
1,153 served87 historical records30 recent
C
HAMLER VILLAGE
580 served89 historical records27 recent
F
MILFORD CITY PWS
6,700 served179 historical records27 recent
C
MAYSVILLE REGIONAL WATER
6,540 served105 historical records19 recent
F
ATTICA VILLAGE
1,148 served89 historical records17 recent
D
KINGSTON VILLAGE PWS
1,032 served46 historical records17 recent
D
ROCK CREEK VILLAGE
667 served97 historical records17 recent
D
NELSONVILLE PWS
6,656 served100 historical records16 recent
F
YORKVILLE VILLAGE PWS
1,019 served48 historical records16 recent
D
Large Systems With No Recent Records
COLUMBUS PUBLIC WATER SYSTEM
1,305,946 served9 historical records
A
CINCINNATI PUBLIC WATER SYSTEM
750,200 served0 historical records
A
TOLEDO CITY OF
360,000 served1 historical record
A
MONTGOMERY COUNTY WATER SERVICES 1 PWS
150,207 served7 historical records
A
DEL-CO WATER COMPANY, INC.
150,000 served29 historical records
A
DAYTON PUBLIC WATER SYSTEM
141,407 served13 historical records
A
YOUNGSTOWN CITY PWS
130,530 served1 historical record
A
AQUA OHIO - MASSILLON PWS
95,636 served0 historical records
A
MONTGOMERY COUNTY WATER SERVICES 2 PWS
83,033 served8 historical records
A
LAKE COUNTY WEST WATER SUBDISTRICT
78,379 served0 historical records
A
Largest Water Systems in Ohio
| Water System | Grade | Population | Historical Records |
|---|---|---|---|
| CLEVELAND PUBLIC WATER SYSTEM | B | 1,308,955 | 45 |
| COLUMBUS PUBLIC WATER SYSTEM | A | 1,305,946 | 9 |
| CINCINNATI PUBLIC WATER SYSTEM | A | 750,200 | 0 |
| TOLEDO CITY OF | A | 360,000 | 1 |
| AKRON CITY PWS | C | 280,000 | 56 |
| MONTGOMERY COUNTY WATER SERVICES 1 PWS | A | 150,207 | 7 |
| DEL-CO WATER COMPANY, INC. | A | 150,000 | 29 |
| DAYTON PUBLIC WATER SYSTEM | A | 141,407 | 13 |
| CLERMONT PUBLIC WATER SYSTEM | B | 133,059 | 19 |
| YOUNGSTOWN CITY PWS | A | 130,530 | 1 |
| BUTLER CO. WATER DISTRICT 2 PWS | C | 116,572 | 7 |
| CANTON PUBLIC WATER SYSTEM | B | 107,113 | 9 |
| AQUA OHIO - MASSILLON PWS | A | 95,636 | 0 |
| MONTGOMERY COUNTY WATER SERVICES 2 PWS | A | 83,033 | 8 |
| WARREN COUNTY | B | 81,975 | 39 |
| LAKE COUNTY WEST WATER SUBDISTRICT | A | 78,379 | 0 |
| AQUA OHIO - MENTOR | B | 74,500 | 3 |
| RURAL LORAIN CO. WATER A | C | 73,125 | 5 |
| ELYRIA WATER DEPARTMENT | B | 68,000 | 18 |
| LIMA CITY | D | 65,619 | 16 |
Contaminants in Ohio
Lead in OhioArsenic in OhioNitrate in OhioFluoride in OhioPFOS in OhioPFOA in OhioTHMs in OhioHAA5 in Ohio
Cities in Ohio
COLUMBUS(17)CLEVELAND(1)CINCINNATI(8)TOLEDO(2)KENT(7)KETTERING(2)HAMILTON(4)DELAWARE(2)DAYTON(7)YOUNGSTOWN(2)BATAVIA(1)LORAIN(4)PAINESVILLE(3)CANTON(5)MENTOR(6)MASSILLON(17)LAGRANGE(4)BOWLING GREEN(10)MARION(3)LIMA(4)TRENTON(2)FAIRFIELD(1)SPRINGFIELD(6)LANCASTER(6)CHILLICOTHE(2)MANSFIELD(19)FINDLAY(1)WARREN(6)ATHENS(2)CUYAHOGA FALLS(3)LAKEWOOD(1)NEWARK(5)PATASKALA(2)NORWALK(6)IRONTON(2)HUBER HEIGHTS(1)MORROW(2)PORTSMOUTH(1)REYNOLDSBURG(1)BARNESVILLE(3)JAMESTOWN(2)ASHTABULA(2)STOW(2)HILLSBORO(2)STEUBENVILLE(5)GLENFORD(2)HURON(7)MARIETTA(6)ZANESVILLE(4)WHITEHOUSE(2)RIPLEY(1)NORTON(1)VIENNA(7)TIPP CITY(2)NORTH RIDGEVILLE(1)XENIA(1)WESTERVILLE(7)LEBANON(5)WOOSTER(10)GALLIPOLIS(2)PORT CLINTON(4)NEW RICHMOND(3)RAVENNA(6)ROSSBURG(1)MEDINA(4)SANDUSKY(1)MARYSVILLE(1)WEST UNION(2)MOUNT VERNON(4)N CANTON(1)MIAMISBURG(3)CIRCLEVILLE(4)WADSWORTH(1)SOMERVILLE(1)AVON(1)AVON LAKE(1)CAMBRIDGE(3)PIQUA(3)ALLIANCE(1)NILES(1)SYLVANIA(1)SIDNEY(2)WAVERLY(4)BALTIMORE(2)ASHLAND(1)DEFIANCE(6)OREGON(1)NORWOOD(1)SPRINGBORO(1)PICKERINGTON(1)BEREA(1)FREMONT(2)TALLMADGE(2)FRANKLIN FURNACE(13)NEW PHILADELPHIA(2)SALEM(3)LONG BOTTOM(1)AURORA(2)MONROE(1)WILLIAMSPORT(4)