| WRIGHT-PATTERSON AFB AREA B PWS Groundwater | OH2903312 | 5 | 3 | |
| MILFORD CITY PWS Groundwater | OH1301012 | 7 | 2 | |
| WRIGHT-PATTERSON AFB AREA A PWS Groundwater | OH2903412 | 7 | 2 | |
| NEWTON FALLS CITY Surface Water | OH7802311 | 7 | 2 | |
| SHADYSIDE PUBLIC WATER SYSTEM Groundwater | OH0701612 | 6 | 2 | |
| TRUMBULL CO.-HOWLAND TWP PWS Surface Water | OH7806303 | 6 | 2 | |
| MONTGOMERY COUNTY WATER SERVICES 1 PWS GU | OH5701315 | 5 | 2 | |
| GRANDVIEW MEDICAL CENTER PWS GU | OH5750615 | 5 | 2 | |
| GIRARD CITY PWS Surface Water | OH7801103 | 5 | 2 | |
| CANFIELD CITY PWS Surface Water | OH5000503 | 4 | 2 | |
| DAYTON VA BLDG 410 GU | OH5750618 | 4 | 2 | |
| MCDONALD VILLAGE PWS Surface Water | OH7802003 | 4 | 2 | |
| SPRINGBORO PWS Groundwater | OH8301412 | 4 | 2 | |
| MARIETTA CITY PWS Groundwater | OH8400412 | 3 | 2 | |
| WILMINGTON CITY PWS Surface Water | OH1401211 | 6 | 1 | |
| DEL-CO WATER COMPANY, INC. Groundwater | OH2101412 | 6 | 1 | |
| SANITARY DISTRICT #4 Surface Water | OH2501003 | 6 | 1 | |
| COLUMBUS PUBLIC WATER SYSTEM Groundwater | OH2504412 | 6 | 1 | |
| TRUMBULL CO.-SOUTHEAST PWS Surface Water | OH7803203 | 6 | 1 | |
| WOOSTER CITY PWS Groundwater | OH8504512 | 6 | 1 | |
| BEXLEY CITY PWS Surface Water | OH2500103 | 5 | 1 | |
| INDIAN HILL CITY PWS Groundwater | OH3101112 | 5 | 1 | |
| HECLA WATER ASSOCIATION-PLANT PWS Surface Water | OH4401612 | 5 | 1 | |
| MONTGOMERY COUNTY WATER SERVICES 2 PWS GU | OH5701503 | 5 | 1 | |
| UNION CITY PWS Groundwater | OH5702512 | 5 | 1 | |
| DAYTON PUBLIC WATER SYSTEM GU | OH5703512 | 5 | 1 | |
| KINGS ISLAND PWS Groundwater | OH8345615 | 5 | 1 | |
| IRONTON PWS Surface Water | OH4400711 | 4 | 1 | |
| LORDSTOWN VILLAGE PWS Surface Water | OH7804403 | 4 | 1 | |
| HAMILTON PUBLIC WATER SYSTEM Groundwater | OH0904012 | 3 | 1 | |
| CLERMONT PUBLIC WATER SYSTEM Groundwater | OH1302212 | 3 | 1 | |
| BELLBROOK WATER WORKS Groundwater | OH2901112 | 3 | 1 | |
| CINCINNATI PUBLIC WATER SYSTEM Groundwater | OH3102612 | 3 | 1 | |
| JACKSON/MILTON METRO WATER DISTRICT PWS Surface Water | OH5054212 | 3 | 1 | |
| NILES CITY PWS Surface Water | OH7802403 | 3 | 1 | |
| MARTINS FERRY PUBLIC WATER SYSTEM Groundwater | OH0701212 | 2 | 1 | |
| LOVELAND CITY PWS Groundwater | OH1300812 | 2 | 1 | |
| GREENVILLE CITY PWS MX | OH1900714 | 2 | 1 | |
| GALLIA CO RURAL WATER ASSOCIATION Groundwater | OH2700012 | 2 | 1 | |
| YELLOW SPRINGS VILLAGE PWS Groundwater | OH2903012 | 2 | 1 | |
| CAMBRIDGE, CITY OF Surface Water | OH3000111 | 2 | 1 | |
| GUERNSEY CO. WATER DEPT. Surface Water | OH3000603 | 2 | 1 | |
| YOUNGSTOWN CITY PWS Surface Water | OH5002303 | 2 | 1 | |
| PORTSMOUTH PUBLIC WATER SYSTEM Surface Water | OH7300111 | 2 | 1 | |
| AKRON CITY PWS Surface Water | OH7700011 | 2 | 1 | |
| PUTNAM COMMUNITY WATER ASSOCIATION PWS Groundwater | OH8400712 | 2 | 1 | |
| WARREN COMM W AND S ASSN 2 Groundwater | OH8402703 | 2 | 1 | |
| BARNESVILLE, OH Surface Water | OH0700011 | 1 | 1 | |
| ST. CLAIRSVILLE, CITY OF PWS Surface Water | OH0701516 | 1 | 1 | |
| GEORGETOWN VILLAGE PWS Groundwater | OH0800503 | 1 | 1 | |
| MIDDLETOWN CITY PWS Groundwater | OH0901712 | 1 | 1 | |
| BETHEL VILLAGE PWS Groundwater | OH1300116 | 1 | 1 | |
| TATE-MONROE WATER ASSOCIATION PWS Groundwater | OH1301312 | 1 | 1 | |
| GALLIPOLIS PWS Groundwater | OH2700112 | 1 | 1 | |
| AQUA OHIO - LAWRENCE COUNTY Surface Water | OH4400803 | 1 | 1 | |
| LEADING CREEK CONSERVANCY DISTRICT Groundwater | OH5300012 | 1 | 1 | |
| CALDWELL VILLAGE PWS Surface Water | OH6100011 | 1 | 1 | |
| FRANKLIN PUBLIC WATER SYSTEM Groundwater | OH8300412 | 1 | 1 | |
| WESTERN WATER COMPANY Groundwater | OH8300512 | 1 | 1 | |
| BLUFFTON VILLAGE Surface Water | OH0200112 | 5 | 0 | |
| WAUSEON CITY Surface Water | OH2600111 | 5 | 0 | |
| OTTAWA VILLAGE Surface Water | OH6900711 | 5 | 0 | |
| FAIRFIELD CITY PWS Groundwater | OH0900715 | 4 | 0 | |
| WELLSTON CITY PWS Groundwater | OH4001912 | 4 | 0 | |
| OBERLIN WATER DEPARTMENT Surface Water | OH4700911 | 4 | 0 | |
| OAKWOOD CITY PWS Groundwater | OH5701915 | 4 | 0 | |
| BOWLING GREEN CITY Surface Water | OH8700311 | 4 | 0 | |
| ELIDA VILLAGE Surface Water | OH0200503 | 3 | 0 | |
| LIMA CITY Surface Water | OH0200811 | 3 | 0 | |
| DEFIANCE CITY Surface Water | OH2000111 | 3 | 0 | |
| CINCINNATI CHILDRENS HOSP IONIZATION SYS Surface Water | OH3139912 | 3 | 0 | |
| NAPOLEON CITY Surface Water | OH3500811 | 3 | 0 | |
| RURAL LORAIN CO. WATER A Groundwater | OH4701803 | 3 | 0 | |
| WATERVILLE CITY Surface Water | OH4801503 | 3 | 0 | |
| JEFFERSON REGIONAL WATER AUTHORITY Groundwater | OH5703012 | 3 | 0 | |
| OTTAWA COUNTY REGIONAL WATER DISTRICT Surface Water | OH6205011 | 3 | 0 | |
| AQUA OHIO - MASSILLON PWS Groundwater | OH7604512 | 3 | 0 | |
| NORTHWESTERN W AND SD- PORTAGE Surface Water | OH8704103 | 3 | 0 | |
| BUTLER CO. WATER DISTRICT 2 PWS Groundwater | OH0900303 | 2 | 0 | |
| TRENTON CITY PWS Groundwater | OH0903012 | 2 | 0 | |
| TORONTO PWS Surface Water | OH4102811 | 2 | 0 | |
| SOUTH POINT VILLAGE Groundwater | OH4401212 | 2 | 0 | |
| ZANESVILLE PWS Groundwater | OH6002712 | 2 | 0 | |
| COMMERCIAL POINT VILLAGE Groundwater | OH6503512 | 2 | 0 | |
| WAVERLY CITY PWS Groundwater | OH6600912 | 2 | 0 | |
| LOUISVILLE CITY PWS Groundwater | OH7603012 | 2 | 0 | |
| BELPRE CITY PWS Groundwater | OH8400012 | 2 | 0 | |
| ASHLAND CITY Groundwater | OH0300112 | 1 | 0 | |
| ANDOVER-CAMPLANDS WATER Groundwater | OH0400212 | 1 | 0 | |
| ATHENS PWS Groundwater | OH0500212 | 1 | 0 | |
| NELSONVILLE PWS Groundwater | OH0501214 | 1 | 0 | |
| NEW BREMEN VILLAGE Groundwater | OH0600512 | 1 | 0 | |
| ST MARYS CITY Groundwater | OH0600612 | 1 | 0 | |
| WAPAKONETA CITY Groundwater | OH0600712 | 1 | 0 | |
| BELLAIRE PUBLIC WATER SYSTEM MX | OH0700114 | 1 | 0 | |
| MOUNT ORAB VILLAGE PWS Surface Water | OH0801011 | 1 | 0 | |
| OXFORD CITY PWS Groundwater | OH0902312 | 1 | 0 | |
| SOUTHWEST REGIONAL WATER DISTRICT Groundwater | OH0903912 | 1 | 0 | |
| URBANA CITY PWS Groundwater | OH1101212 | 1 | 0 | |
| NEW CARLISLE CITY PWS Groundwater | OH1203312 | 1 | 0 | |
| BLANCHESTER VILLAGE PWS Surface Water | OH1400111 | 1 | 0 | |
| COLUMBIANA CITY PWS Groundwater | OH1500312 | 1 | 0 | |
| EAST LIVERPOOL CITY Surface Water | OH1500811 | 1 | 0 | |
| CRESTLINE VILLAGE Groundwater | OH1700112 | 1 | 0 | |
| GALION CITY Surface Water | OH1700211 | 1 | 0 | |
| BEREA CITY PWS Surface Water | OH1800111 | 1 | 0 | |
| CHAGRIN FALLS VILLAGE PWS Groundwater | OH1800212 | 1 | 0 | |
| UNIVERSITY HOSPITALS - MAIN CAMPUS Surface Water | OH1841113 | 1 | 0 | |
| HICKSVILLE VILLAGE Groundwater | OH2000212 | 1 | 0 | |
| DELAWARE CITY PWS MX | OH2100311 | 1 | 0 | |
| LANCASTER CITY PWS Groundwater | OH2301012 | 1 | 0 | |
| GREENFIELD TWP WATER DISTRICT Groundwater | OH2301812 | 1 | 0 | |
| FAIRFIELD COUNTY UTILITIES PWS Groundwater | OH2301912 | 1 | 0 | |
| GROVEPORT PWS Groundwater | OH2501512 | 1 | 0 | |
| AQUA OHIO - LAKE DARBY Groundwater | OH2502612 | 1 | 0 | |
| REYNOLDSBURG CITY PWS Surface Water | OH2503203 | 1 | 0 | |
| WESTERVILLE CITY PWS MX | OH2503411 | 1 | 0 | |
| JEFFERSON WATER AND SEWER DISTRICT PWS Groundwater | OH2504012 | 1 | 0 | |
| DELTA VILLAGE Surface Water | OH2600311 | 1 | 0 | |
| SWANTON VILLAGE MX | OH2601011 | 1 | 0 | |
| CHARDON CITY PWS Groundwater | OH2800412 | 1 | 0 | |
| SCRANTON WOODS Groundwater | OH2803712 | 1 | 0 | |
| BYESVILLE GU | OH3001212 | 1 | 0 | |
| READING CITY PWS Surface Water | OH3101812 | 1 | 0 | |
| WYOMING CITY PWS Groundwater | OH3102212 | 1 | 0 | |
| ADA VILLAGE Groundwater | OH3300012 | 1 | 0 | |
| KENTON CITY Groundwater | OH3300612 | 1 | 0 | |
| BELLEVUE CITY Surface Water | OH3900011 | 1 | 0 | |
| NORWALK CITY Surface Water | OH3901111 | 1 | 0 | |
| NORW - SOUTH DISTRICT Surface Water | OH3946712 | 1 | 0 | |
| JACKSON, CITY OF Surface Water | OH4000111 | 1 | 0 | |
| JEFFERSON CO W AND S DISTRICT- A Groundwater | OH4100803 | 1 | 0 | |
| JEFFERSON CO W AND S DISTRICT - M Surface Water | OH4101103 | 1 | 0 | |
| JOHNSTOWN VILLAGE PWS Groundwater | OH4501512 | 1 | 0 | |
| NEWARK CITY PWS Surface Water | OH4502314 | 1 | 0 | |
| PATASKALA CITY Groundwater | OH4502512 | 1 | 0 | |
| BELLEFONTAINE CITY PWS Groundwater | OH4600112 | 1 | 0 | |
| HONDA EAST LIBERTY WTP Groundwater | OH4643512 | 1 | 0 | |
| OREGON CITY, OH Surface Water | OH4800911 | 1 | 0 | |
| TOLEDO, CITY OF Surface Water | OH4801411 | 1 | 0 | |
| WHITEHOUSE VILLAGE Surface Water | OH4801612 | 1 | 0 | |
| LONDON CITY PWS Groundwater | OH4900712 | 1 | 0 | |
| MADISON COUNTY SSWD WATER DISTRICT 1 Groundwater | OH4901012 | 1 | 0 | |
| MID-OHIO WSD PLAIN CITY WTP Groundwater | OH4901112 | 1 | 0 | |
| AQUA OHIO - STRUTHERS Surface Water | OH5001611 | 1 | 0 | |
| AQUA OHIO - MARION MX | OH5100414 | 1 | 0 | |
| MEDINA CITY PWS Surface Water | OH5200514 | 1 | 0 | |
| MEDINA CO/NORTHWEST PWS Surface Water | OH5201903 | 1 | 0 | |
| MEDINA CO/SOUTHERN WATER DIST PWS Groundwater | OH5260712 | 1 | 0 | |
| CELINA CITY Surface Water | OH5400011 | 1 | 0 | |
| COLDWATER VILLAGE Groundwater | OH5400112 | 1 | 0 | |
| PIQUA CITY PWS Surface Water | OH5501211 | 1 | 0 | |
| BROOKVILLE MUNICIPALITY PWS GU | OH5700203 | 1 | 0 | |
| TROTWOOD CITY PWS GU | OH5702403 | 1 | 0 | |
| MT GILEAD VILLAGE PWS Groundwater | OH5900712 | 1 | 0 | |
| MUSKINGUM COUNTY WATER - SE Groundwater | OH6000412 | 1 | 0 | |
| MAYSVILLE REGIONAL WATER Surface Water | OH6001411 | 1 | 0 | |
| PAULDING VILLAGE Surface Water | OH6300411 | 1 | 0 | |
| ASHVILLE VILLAGE PWS Groundwater | OH6500012 | 1 | 0 | |
| CIRCLEVILLE CITY PWS Groundwater | OH6500412 | 1 | 0 | |
| EARNHART HILL WATER DISTRICT PWS Groundwater | OH6500812 | 1 | 0 | |
| ODRC-PICKAWAY CORRECTION PWS Groundwater | OH6501712 | 1 | 0 | |
| PIKE WATER, INC.-PLANT PWS Groundwater | OH6602412 | 1 | 0 | |
| PORTAGE COUNTY WATER RESOURCES Groundwater | OH6702812 | 1 | 0 | |
| RAVENNA CITY PWS Surface Water | OH6703211 | 1 | 0 | |
| COLUMBUS GROVE VILLAGE Groundwater | OH6900112 | 1 | 0 | |
| ONTARIO CITY Groundwater | OH7003512 | 1 | 0 | |
| SHELBY CITY Surface Water | OH7004511 | 1 | 0 | |
| GB FABRICATION Groundwater | OH7049512 | 1 | 0 | |
| CHILLICOTHE CITY PWS Groundwater | OH7100112 | 1 | 0 | |
| ROSS COUNTY WATER CO INC PWS Groundwater | OH7101412 | 1 | 0 | |
| CLYDE CITY Surface Water | OH7200211 | 1 | 0 | |
| FREMONT CITY Surface Water | OH7200311 | 1 | 0 | |
| NORTHWEST REGIONAL WATER DISTRICT Groundwater | OH7300003 | 1 | 0 | |
| SCIOTO CO. REGIONAL WATER DISTRICT #1 Groundwater | OH7300212 | 1 | 0 | |
| SCIOTO WATER, INC.-SUGAR CAMP Groundwater | OH7300903 | 1 | 0 | |
| AQUA OHIO - TIFFIN MX | OH7400614 | 1 | 0 | |
| HONDA - ANNA ENGINE PLANT Groundwater | OH7537812 | 1 | 0 | |
| ALLIANCE CITY PWS Surface Water | OH7600011 | 1 | 0 | |
| CANAL FULTON CITY PWS Groundwater | OH7600912 | 1 | 0 | |
| NORTH CANTON CITY PWS Groundwater | OH7604312 | 1 | 0 | |
| STARK COUNTY WATER DISTRICT Groundwater | OH7607303 | 1 | 0 | |
| CANTON PUBLIC WATER SYSTEM Groundwater | OH7608112 | 1 | 0 | |
| CUYAHOGA FALLS CITY PWS Groundwater | OH7701012 | 1 | 0 | |
| HUDSON CITY PWS Groundwater | OH7701612 | 1 | 0 | |
| OLD TRAIL SCHOOL Groundwater | OH7754712 | 1 | 0 | |
| MANCHESTER HIGH SCHOOL Groundwater | OH7778012 | 1 | 0 | |
| CORTLAND CITY PWS Groundwater | OH7800512 | 1 | 0 | |
| HUBBARD CITY PWS Surface Water | OH7801415 | 1 | 0 | |
| AQUA OHIO - MASURY Surface Water | OH7802711 | 1 | 0 | |
| WARREN CITY PWS Surface Water | OH7803811 | 1 | 0 | |
| TRUMBULL CO. - BAZETTA/CHAMPION Surface Water | OH7804303 | 1 | 0 | |
| MARYSVILLE CITY PWS MX | OH8000314 | 1 | 0 | |
| HONDA - BENTON RD. WTP Groundwater | OH8035512 | 1 | 0 | |
| LEBANON CITY Surface Water | OH8304112 | 1 | 0 | |
| WARREN CO. SOCIALVILLE PWS Surface Water | OH8304203 | 1 | 0 | |
| LITTLE HOCKING WATER ASSOCIATION, INC. Groundwater | OH8400212 | 1 | 0 | |
| WATERFORD WATER/SEWER ASSOCIATION Groundwater | OH8401112 | 1 | 0 | |
| ORRVILLE CITY PWS Groundwater | OH8502712 | 1 | 0 | |
| RITTMAN CITY PWS Groundwater | OH8503012 | 1 | 0 | |
| BRYAN CITY Groundwater | OH8600012 | 1 | 0 | |
| MONTPELIER VILLAGE Groundwater | OH8600912 | 1 | 0 | |
| NORTH BALTIMORE VILLAGE Surface Water | OH8701611 | 1 | 0 | |
| NORTHWESTERN W AND SD - WTLN 200 Surface Water | OH8704203 | 1 | 0 | |