| MCDONALD VILLAGE PWS | | 4,236 | 0.0212 ug/L |
| GIRARD CITY | | 14,122 | 0.0201 ug/L |
| WARREN COMM W AND S ASSN 2 | | 7,215 | 0.0200 ug/L |
| YOUNGSTOWN CITY PWS | | 130,530 | 0.0193 ug/L |
| PUTNAM COMMUNITY WATER ASSOCIATION PWS | | 2,744 | 0.0169 ug/L |
| LOVELAND CITY PWS | | 12,800 | 0.0160 ug/L |
| LORDSTOWN VILLAGE PWS | | 3,515 | 0.0160 ug/L |
| WESTERN WATER COMPANY | | 39,508 | 0.0141 ug/L |
| TRUMBULL CO. - HOWLAND TWP PWS | | 6,396 | 0.0130 ug/L |
| CALDWELL VILLAGE PWS | | 3,300 | 0.0130 ug/L |
| INDIAN HILL CITY PWS | | 15,000 | 0.0124 ug/L |
| CANFIELD CITY PWS | | 7,706 | 0.0124 ug/L |
| DAYTON VA BLDG 410 | | 125 | 0.0105 ug/L |
| CLERMONT PUBLIC WATER SYSTEM | | 133,059 | 0.0101 ug/L |
| DAYTON PUBLIC WATER SYSTEM | | 141,407 | 0.0100 ug/L |
| GUERNSEY CO. WATER DEPT. | | 8,891 | 0.0098 ug/L |
| MONTGOMERY COUNTY WATER SERVICES 1 PWS | | 150,207 | 0.0096 ug/L |
| YELLOW SPRINGS VILLAGE PWS | | 3,761 | 0.0092 ug/L |
| TRUMBULL CO. - SOUTHEAST PWS | | 9,931 | 0.0091 ug/L |
| NILES CITY PWS | | 21,961 | 0.0090 ug/L |
| BARNESVILLE | | 6,500 | 0.0081 ug/L |
| JACKSON/MILTON METRO WATER DISTRICT PWS | | 3,728 | 0.0079 ug/L |
| BETHEL VILLAGE PWS | | 2,620 | 0.0079 ug/L |
| MILFORD CITY PWS | | 6,700 | 0.0078 ug/L |
| MONTGOMERY COUNTY WATER SERVICES 2 PWS | | 83,033 | 0.0076 ug/L |
| LEADING CREEK CONSERVANCY DISTRICT | | 6,663 | 0.0076 ug/L |
| GALLIA CO RURAL WATER ASSOCIATION | | 20,995 | 0.0075 ug/L |
| TATE-MONROE WATER ASSOCIATION PWS | | 24,092 | 0.0074 ug/L |
| AKRON CITY PWS | | 280,000 | 0.0073 ug/L |
| WILMINGTON CITY PWS | | 12,401 | 0.0073 ug/L |
| SANITARY DISTRICT #4 | | 8,575 | 0.0072 ug/L |
| GALLIPOLIS PWS | | 7,134 | 0.0072 ug/L |
| SPRINGBORO PWS | | 19,263 | 0.0069 ug/L |
| HECLA WATER ASSOCIATION | | 34,942 | 0.0068 ug/L |
| NEWTON FALLS CITY | | 6,109 | 0.0067 ug/L |
| ST. CLAIRSVILLE, CITY OF PWS | | 5,097 | 0.0064 ug/L |
| GREENVILLE CITY PWS | | 13,227 | 0.0063 ug/L |
| CINCINNATI PUBLIC WATER SYSTEM | | 750,200 | 0.0061 ug/L |
| MARTINS FERRY PUBLIC WATER SYSTEM | | 6,980 | 0.0061 ug/L |
| SHADYSIDE PUBLIC WATER SYSTEM | | 3,689 | 0.0060 ug/L |
| MARIETTA CITY PWS | | 18,707 | 0.0056 ug/L |
| BEXLEY CITY PWS | | 14,250 | 0.0056 ug/L |
| CAMBRIDGE, CITY OF | | 10,520 | 0.0056 ug/L |
| IRONTON | | 11,129 | 0.0055 ug/L |
| PORTSMOUTH CITY | | 40,475 | 0.0054 ug/L |
| COLUMBUS PUBLIC WATER SYSTEM | | 1,305,946 | 0.0053 ug/L |
| HAMILTON PUBLIC WATER SYSTEM | | 62,447 | 0.0053 ug/L |
| WOOSTER CITY PWS | | 26,618 | 0.0048 ug/L |
| UNION CITY PWS | | 7,000 | 0.0048 ug/L |
| GEORGETOWN VILLAGE PWS | | 4,331 | 0.0047 ug/L |
| MIDDLETOWN CITY PWS | | 51,229 | 0.0043 ug/L |
| DEL-CO WATER COMPANY, INC. | | 150,000 | 0.0042 ug/L |
| BELLBROOK WATER WORKS | | 9,475 | 0.0042 ug/L |
| AQUA OHIO - LAWRENCE COUNTY | | 8,130 | 0.0042 ug/L |
| FRANKLIN PUBLIC WATER SYSTEM | | 11,690 | 0.0041 ug/L |
| MAYSVILLE REGIONAL WATER | | 6,540 | 0.0040 ug/L |
| CLEVELAND PUBLIC WATER SYSTEM | | 1,308,955 | Not detected |
| TOLEDO CITY OF | | 360,000 | Not detected |
| BUTLER CO. WATER DISTRICT 2 PWS | | 116,572 | Not detected |
| CANTON PUBLIC WATER SYSTEM | | 107,113 | Not detected |
| AQUA OHIO - MASSILLON PWS | | 95,636 | Not detected |
| LAKE COUNTY WEST WATER SUBDISTRICT | | 78,379 | Not detected |
| AQUA OHIO - MENTOR | | 74,500 | Not detected |
| RURAL LORAIN CO. WATER A | | 73,125 | Not detected |
| ELYRIA WATER DEPARTMENT | | 68,000 | Not detected |
| LIMA CITY | | 65,619 | Not detected |
| LORAIN CITY PWS | | 64,152 | Not detected |
| SPRINGFIELD CITY PWS | | 60,680 | Not detected |
| FINDLAY CITY PWS | | 54,040 | Not detected |
| CUYAHOGA FALLS CITY PWS | | 51,114 | Not detected |
| MANSFIELD CITY | | 51,000 | Not detected |
| LAKEWOOD CITY PWS | | 50,942 | Not detected |
| NEWARK CITY PWS | | 49,934 | Not detected |
| WARREN CITY PWS | | 49,130 | Not detected |
| AQUA OHIO - MARION | | 47,102 | Not detected |
| FAIRFIELD CITY PWS | | 44,907 | Not detected |
| DELAWARE CITY PWS | | 43,895 | Not detected |
| HUBER HEIGHTS PUBLIC WATER SYSTEM | | 43,439 | Not detected |
| SOUTHWEST REGIONAL WATER DISTRICT | | 42,856 | Not detected |
| LAKE COUNTY EAST WATER SUBDISTRICT | | 40,656 | Not detected |
| LANCASTER CITY PWS | | 40,400 | Not detected |
| WESTERVILLE CITY PWS | | 39,000 | Not detected |
| REYNOLDSBURG CITY PWS | | 37,847 | Not detected |
| STOW PUBLIC WATER SYSTEM | | 35,437 | Not detected |
| ROSS COUNTY WATER CO INC | | 35,345 | Not detected |
| FAIRBORN PUBLIC WATER SYSTEM | | 34,620 | Not detected |
| GAHANNA CITY PWS | | 33,258 | Not detected |
| ATHENS PWS | | 32,725 | Not detected |
| AQUA OHIO - ASHTABULA | | 32,342 | Not detected |
| BROWN COUNTY RURAL WATER | | 32,090 | Not detected |
| PAINESVILLE CITY PWS | | 31,728 | Not detected |
| BOWLING GREEN CITY | | 31,578 | Not detected |
| BARBERTON CITY | | 31,298 | Not detected |
| NAWA | | 29,974 | Not detected |
| KENT CITY PWS | | 29,662 | Not detected |
| NORTH RIDGEVILLE CITY PWS | | 29,465 | Not detected |
| ZANESVILLE PWS | | 29,381 | Not detected |
| XENIA CITY PWS | | 29,000 | Not detected |
| HIGHLAND COUNTY WATER COMPANY, INC. | | 28,421 | Not detected |
| PERRYSBURG CITY PWS | | 27,000 | Not detected |