Ohio Hometown AtlasHometown Atlas

Water systems

1,131 community water systems serve Ohio's homes and businesses. Every ZIP code on this site is colored by the system serving the most of its residents, traced through any wholesale purchase to the utility that actually treats the water.

Where Ohio's tap water comes from

  • Groundwater32% · 3,357,565 people
  • Lake Erie26% · 2,727,890 people
  • Inland river21% · 2,224,906 people
  • Reservoir or inland lake11% · 1,125,163 people
  • Ohio River10% · 1,019,659 people

U.S. EPA SDWIS and Community Water System Service Area Boundaries (v3, 2026), Ohio EPA primacy data, 2020 census blocks: the system serving most residents, traced through purchases to the treating utility; Ohio EPA 2023 Sewer and Water Rate Survey (Ohio State, May 2025) for household bills; Ohio EPA DEFA loan awards since 2016 for the loans paragraph · EPA SDWIS · EPA service area boundaries · Ohio EPA drinking water · Ohio EPA rate survey

The 50 largest systems

Ranked by people served (EPA SDWIS)
#SystemCountyPeople servedSource
1Cleveland Public Water System OH1801212Cuyahoga1,308,955Lake Erie
2Columbus Public Water System OH2504412Franklin1,305,946Scioto River (Griggs & O'Shaughnessy), Hoover Reservoir on Big Walnut Ck, plus wells
3Cincinnati Public Water System OH3102612Hamilton750,200Ohio River (Miller Plant, ~88%) plus Great Miami Buried Valley Aquifer wells (~12%)
4Toledo City Of OH4801411Lucas360,000Lake Erie
5Akron City OH7700011Summit280,000Lake Rockwell (Cuyahoga River impoundment)
6Montgomery County Water Services 1 OH5701315Montgomery150,207Great Miami Buried Valley Aquifer wells (recharged by Great Miami & Mad Rivers)
7Del-co Water Company, Inc. OH2101412Delaware150,000Olentangy River, O'Shaughnessy and Alum Creek reservoirs, plus Knox County wells
8Dayton Public Water System OH5703512Montgomery141,407Great Miami Buried Valley Aquifer wells (recharged by Great Miami & Mad Rivers)
9Clermont Public Water System OH1302212Clermont133,059William H. Harsha Lake plus wells in the Little Miami River and Ohio River aquifers
10Youngstown City OH5002303Mahoning130,530Meander Creek Reservoir + Berlin Reservoir (Mahoning River basin)
11Butler Co. Water District 2 OH0900303Butler116,572Hamilton wells (Great Miami aquifer) + Cincinnati (Ohio River + wells)
12Canton Public Water System OH7608112Stark107,113Glacial sand-and-gravel aquifer (3 well fields)
13West Virginia American Water - Huntington WV3300608West Virginia98,647Ohio River (with Guyandotte River backup intake)
14Aqua Ohio - Massillon OH7604512Stark95,636Wells in Tuscarawas Valley sand & gravel aquifer
15Montgomery County Water Services 2 OH5701503Montgomery83,033Great Miami Buried Valley Aquifer wells (recharged by Great Miami & Mad Rivers)
16Warren County OH8301512Warren81,975Wells in the Little Miami and Great Miami river valley aquifers
17Lake County West Water Subdistrict OH4302411Lake78,379Lake Erie
18Aqua Ohio - Mentor OH4301511Lake74,500Lake Erie
19Rural Lorain Co. Water A OH4701803Lorain73,125Mostly Lake Erie (bought from Avon Lake); some New London Reservoir and Ashland wells
20Elyria Water Department OH4700411Lorain68,000Lake Erie
21Lima City OH0200811Allen65,619Auglaize River and Ottawa River, stored in city upground reservoirs
22Lorain City OH4700711Lorain64,152Lake Erie
23Hamilton Public Water System OH0904012Butler62,447Great Miami Buried Valley Aquifer (wells)
24Springfield City OH1204412Clark60,680Mad River Buried Valley Aquifer (12 wells)
25Aqua Ohio - Struthers OH5001611Mahoning58,551Evans Lake (Yellow Creek impoundment)
26Findlay City OH3200111Hancock54,040Findlay's two upground reservoirs, filled by pumping from the Blanchard River
27Middletown City OH0901712Butler51,229Great Miami Buried Valley Aquifer (wells)
28Cuyahoga Falls City OH7701012Summit51,114Wells in Cuyahoga River buried valley sand & gravel aquifer
29Mansfield City OH7002914Richland51,000Clear Fork Reservoir (Clear Fork of the Mohican River), plus 9 city wells
30Lakewood City OH1801003Cuyahoga50,942Lake Erie
31Newark City OH4502314Licking49,934North Fork Licking River
32Warren City OH7803811Trumbull49,130Mosquito Creek Lake (Mosquito Creek Reservoir)
33Aqua Pennsylvania - Shenango Valley (Sharon, PA) PA6430054Pennsylvania48,000Shenango River / Shenango River Lake (Pymatuning area) surface intake
34Aqua Ohio - Marion OH5100414Marion47,102Scioto River and Little Scioto River intakes, blended with local groundwater wells
35Medina Co/northwest OH5201903Medina46,324Lake Erie
36Fairfield City OH0900715Butler44,907Great Miami Buried Valley Aquifer (wells)
37Delaware City OH2100311Delaware43,895Olentangy River (blended with deep wells)
38Huber Heights Public Water System OH5703612Montgomery43,439Great Miami Buried Valley Aquifer (wells)
39Southwest Regional Water District OH0903912Butler42,856Great Miami Buried Valley Aquifer (wells)
40Greene County - northwest Reg Water OH2903512Greene41,895Little Miami River Buried Valley Aquifer (2 wellfields, Beavercreek area)
41Lake County East Water Subdistrict OH4302911Lake40,656Lake Erie
42Portsmouth City OH7300111Scioto40,475Ohio River
43Lancaster City OH2301012Fairfield40,400Hocking River Valley Aquifer (wells)
44Western Water Company OH8300512Warren39,508Little Miami River valley wells (51%) plus Cincinnati Ohio River water (49%)
45Westerville City OH2503411Franklin39,000Alum Creek + wells
46Reynoldsburg City OH2503203Franklin37,847Scioto River (Griggs & O'Shaughnessy), Hoover Reservoir on Big Walnut Ck, plus wells
47Stow Public Water System OH7704503Summit35,437Lake Rockwell (Cuyahoga River impoundment)
48Ross County Water Co. Inc OH7101412Ross35,345Teays Valley Aquifer (buried valley groundwater)
49Hecla Water Association OH4401612Lawrence34,942Ohio River
50Fairborn Public Water System OH2900612Greene34,620Mad River Buried Valley Aquifer (Mad River Well Field, wells)

Every system, A to Z

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Cite this page as:

Ohio Hometown Atlas (Open Shower Co), "Water systems", https://hometownatlas.openshowerco.com/water/, built 2026-09-15, accessed [date].

Machine-readable: /api/water.json (open JSON, CC BY 4.0 for the compilation; the underlying records keep their own terms) · How to cite · Report a correction · Built 2026-09-15