| CLEVELAND PUBLIC WATER SYSTEM | | 1,308,955 | 0.0130 mg/L |
| COLUMBUS PUBLIC WATER SYSTEM | | 1,305,946 | 0.0177 mg/L |
| CINCINNATI PUBLIC WATER SYSTEM | | 750,200 | 0.0095 mg/L |
| TOLEDO CITY OF | | 360,000 | 0.0075 mg/L |
| AKRON CITY PWS | | 280,000 | 0.0083 mg/L |
| MONTGOMERY COUNTY WATER SERVICES 1 PWS | | 150,207 | 0.0037 mg/L |
| DEL-CO WATER COMPANY, INC. | | 150,000 | 0.0059 mg/L |
| DAYTON PUBLIC WATER SYSTEM | | 141,407 | 0.0068 mg/L |
| CLERMONT PUBLIC WATER SYSTEM | | 133,059 | 0.0050 mg/L |
| YOUNGSTOWN CITY PWS | | 130,530 | 0.0021 mg/L |
| BUTLER CO. WATER DISTRICT 2 PWS | | 116,572 | 0.0146 mg/L |
| CANTON PUBLIC WATER SYSTEM | | 107,113 | 0.0081 mg/L |
| AQUA OHIO - MASSILLON PWS | | 95,636 | 0.0043 mg/L |
| MONTGOMERY COUNTY WATER SERVICES 2 PWS | | 83,033 | 0.0070 mg/L |
| LAKE COUNTY WEST WATER SUBDISTRICT | | 78,379 | 0.0110 mg/L |
| AQUA OHIO - MENTOR | | 74,500 | 0.0060 mg/L |
| RURAL LORAIN CO. WATER A | | 73,125 | 0.0112 mg/L |
| ELYRIA WATER DEPARTMENT | | 68,000 | 0.0080 mg/L |
| LIMA CITY | | 65,619 | 0.0047 mg/L |
| LORAIN CITY PWS | | 64,152 | 0.0074 mg/L |
| HAMILTON PUBLIC WATER SYSTEM | | 62,447 | 0.0131 mg/L |
| SPRINGFIELD CITY PWS | | 60,680 | 0.0050 mg/L |
| FINDLAY CITY PWS | | 54,040 | 0.0118 mg/L |
| MIDDLETOWN CITY PWS | | 51,229 | 0.0050 mg/L |
| CUYAHOGA FALLS CITY PWS | | 51,114 | 0.0078 mg/L |
| MANSFIELD CITY | | 51,000 | 0.0110 mg/L |
| LAKEWOOD CITY PWS | | 50,942 | 0.0072 mg/L |
| NEWARK CITY PWS | | 49,934 | 0.0370 mg/L |
| WARREN CITY PWS | | 49,130 | 0.0103 mg/L |
| AQUA OHIO - MARION | | 47,102 | 0.0040 mg/L |
| FAIRFIELD CITY PWS | | 44,907 | 0.0109 mg/L |
| DELAWARE CITY PWS | | 43,895 | 0.0120 mg/L |
| HUBER HEIGHTS PUBLIC WATER SYSTEM | | 43,439 | 0.0068 mg/L |
| SOUTHWEST REGIONAL WATER DISTRICT | | 42,856 | 0.0050 mg/L |
| LAKE COUNTY EAST WATER SUBDISTRICT | | 40,656 | 0.0090 mg/L |
| PORTSMOUTH CITY | | 40,475 | 0.0090 mg/L |
| LANCASTER CITY PWS | | 40,400 | 0.0047 mg/L |
| WESTERN WATER COMPANY | | 39,508 | 0.0060 mg/L |
| WESTERVILLE CITY PWS | | 39,000 | 0.0110 mg/L |
| REYNOLDSBURG CITY PWS | | 37,847 | 0.0185 mg/L |
| STOW PUBLIC WATER SYSTEM | | 35,437 | 0.0052 mg/L |
| ROSS COUNTY WATER CO INC | | 35,345 | 0.0050 mg/L |
| HECLA WATER ASSOCIATION | | 34,942 | 0.0071 mg/L |
| FAIRBORN PUBLIC WATER SYSTEM | | 34,620 | 0.0050 mg/L |
| GAHANNA CITY PWS | | 33,258 | 0.0186 mg/L |
| ATHENS PWS | | 32,725 | 0.0045 mg/L |
| AQUA OHIO - ASHTABULA | | 32,342 | 0.0080 mg/L |
| BROWN COUNTY RURAL WATER | | 32,090 | 0.0076 mg/L |
| PAINESVILLE CITY PWS | | 31,728 | 0.0149 mg/L |
| BOWLING GREEN CITY | | 31,578 | 0.0100 mg/L |
| BARBERTON CITY | | 31,298 | 0.0070 mg/L |
| NAWA | | 29,974 | 0.0036 mg/L |
| KENT CITY PWS | | 29,662 | 0.0029 mg/L |
| NORTH RIDGEVILLE CITY PWS | | 29,465 | 0.0144 mg/L |
| ZANESVILLE PWS | | 29,381 | 0.0093 mg/L |
| XENIA CITY PWS | | 29,000 | 0.0050 mg/L |
| HIGHLAND COUNTY WATER COMPANY, INC. | | 28,421 | 0.0066 mg/L |
| PERRYSBURG CITY PWS | | 27,000 | 0.0060 mg/L |
| BELMONT CO. SANITARY DISTRICT 3 PWS | | 26,822 | 0.0027 mg/L |
| WOOSTER CITY PWS | | 26,618 | 0.0034 mg/L |
| TROY CITY PWS | | 26,305 | 0.0050 mg/L |
| MEDINA CITY PWS | | 25,956 | 0.0044 mg/L |
| SANDUSKY CITY | | 25,793 | 0.0090 mg/L |
| MARYSVILLE CITY PWS | | 25,571 | 0.0039 mg/L |
| NORTH CANTON CITY PWS | | 24,747 | 0.0028 mg/L |
| WADSWORTH CITY PWS | | 24,356 | 0.0023 mg/L |
| TATE-MONROE WATER ASSOCIATION PWS | | 24,092 | 0.0102 mg/L |
| OXFORD CITY PWS | | 24,000 | 0.0068 mg/L |
| AVON CITY PWS | | 23,800 | 0.0140 mg/L |
| AVON LAKE CITY PWS | | 23,659 | 0.0063 mg/L |
| ALLIANCE CITY PWS | | 22,232 | 0.0119 mg/L |
| NILES CITY PWS | | 21,961 | 0.0040 mg/L |
| ADAMS COUNTY REGIONAL WD PWS | | 21,810 | 0.0044 mg/L |
| CHILLICOTHE CITY PWS | | 21,725 | 0.0022 mg/L |
| SYLVANIA CITY | | 21,618 | 0.0230 mg/L |
| GALLIA CO RURAL WATER ASSOCIATION | | 20,995 | 0.0094 mg/L |
| LEBANON CITY | | 20,700 | 0.0074 mg/L |
| ASHLAND CITY | | 20,648 | 0.0022 mg/L |
| SIDNEY CITY PWS | | 20,614 | 0.0130 mg/L |
| OTTAWA COUNTY REGIONAL WATER DISTRICT | | 20,428 | 0.0080 mg/L |
| PIQUA CITY PWS | | 20,354 | 0.0077 mg/L |
| AQUA OHIO - TIFFIN | | 20,279 | 0.0130 mg/L |
| OREGON CITY | | 19,950 | 0.0120 mg/L |
| NORWOOD CITY PWS | | 19,870 | 0.0051 mg/L |
| MIAMISBURG CITY PWS | | 19,790 | 0.0070 mg/L |
| NORTHWESTERN W AND SD - TOLEDO SVC AREA | | 19,758 | 0.0069 mg/L |
| LE-AX REGIONAL WATER DISTRICT PWS | | 19,311 | 0.0050 mg/L |
| SPRINGBORO PWS | | 19,263 | 0.0124 mg/L |
| PICKERINGTON CITY PWS | | 19,141 | 0.0053 mg/L |
| BEREA CITY PWS | | 18,789 | 0.0073 mg/L |
| MARIETTA CITY PWS | | 18,707 | 0.0010 mg/L |
| TALLMADGE CITY PWS | | 18,394 | 0.0083 mg/L |
| FREMONT CITY | | 18,319 | 0.0090 mg/L |
| NORTHERN OHIO RURAL WATER | | 18,224 | 0.0140 mg/L |
| LICKING REGIONAL WATER DISTRICT | | 17,818 | 0.0064 mg/L |
| NORWALK CITY PWS | | 17,466 | 0.0059 mg/L |
| NEW PHILADELPHIA CITY PWS | | 17,410 | 0.0055 mg/L |
| ERIE CO PERKINS DISTRICT | | 17,241 | 0.0139 mg/L |
| STEUBENVILLE, CITY OF | | 17,000 | 0.0023 mg/L |
| MOUNT VERNON CITY PWS | | 16,990 | 0.0031 mg/L |