All water systems in Ohio
4,165 systems
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Columbus Public Water System Franklin County |
1,309,468 | 0 | 0 | |
|
Cleveland Public Water System Cuyahoga County |
1,308,955 | 1 | 0 | |
|
Cincinnati Public Water System Hamilton County |
800,000 | 0 | 0 | |
|
Toledo City of Lucas County |
360,000 | 2 | 0 | |
|
Akron City PWS Summit County |
280,000 | 1 | 0 | |
|
Montgomery County Water Services 1 PWS Montgomery County |
150,207 | 0 | 0 | |
|
Del-Co Water Company, Inc. Delaware County |
150,000 | 0 | 0 | |
|
Dayton Public Water System Montgomery County |
141,407 | 0 | 0 | |
|
Clermont Public Water System Clermont County |
133,059 | 1 | 1 | |
|
Youngstown City PWS Mahoning County |
130,530 | 1 | 0 | |
|
Butler Co. Water District 2 PWS Butler County |
116,572 | 1 | 0 | |
|
Canton Public Water System Stark County |
107,113 | 1 | 1 | |
|
Warren County Warren County |
99,000 | 1 | 1 | |
|
Aqua Ohio Massillon PWS Stark County |
95,636 | 1 | 1 | |
|
Montgomery County Water Services 2 PWS Montgomery County |
83,033 | 0 | 0 | |
|
Lake County West Water Subdistrict Lake County |
78,379 | 1 | 0 | |
|
Aqua Ohio Mentor Lake County |
74,500 | 1 | 0 | |
|
Rural Lorain Co. Water a Lorain County |
73,125 | 1 | 0 | |
|
Elyria Water Department Lorain County |
68,000 | 0 | 0 | |
|
Lima City Allen County |
65,619 | 2 | 0 | |
|
Lorain City PWS Lorain County |
64,152 | 2 | 1 | |
|
Hamilton Public Water System Butler County |
62,447 | 2 | 1 | |
|
Springfield City PWS Clark County |
60,680 | 1 | 1 | |
|
Aqua Ohio Struthers Mahoning County |
58,551 | 1 | 1 | |
|
Findlay City PWS Hancock County |
54,040 | 1 | 1 | |
|
Middletown City PWS Butler County |
51,229 | 2 | 1 | |
|
Cuyahoga Falls City PWS Summit County |
51,114 | 2 | 1 | |
|
Mansfield City Richland County |
51,000 | 4 | 1 | |
|
Lakewood City PWS Cuyahoga County |
50,942 | 3 | 0 | |
|
Newark City PWS Licking County |
49,934 | 2 | 1 | |
|
Warren City PWS Trumbull County |
49,130 | 1 | 0 | |
|
Aqua Ohio Marion Marion County |
47,102 | 0 | 0 | |
|
Medina Co/northwest PWS Medina County |
46,324 | 2 | 2 | |
|
Fairfield City PWS Butler County |
44,907 | 0 | 0 | |
|
Delaware City PWS Delaware County |
43,895 | 1 | 1 | |
|
Huber Heights Public Water System Montgomery County |
43,439 | 1 | 1 | |
|
Southwest Regional Water District Butler County |
42,856 | 0 | 0 | |
|
Greene Co.-Northwest Reg Water Greene County |
41,895 | 1 | 0 | |
|
Lake County East Water Subdistrict Lake County |
40,656 | 0 | 0 | |
|
Portsmouth City Scioto County |
40,475 | 2 | 1 | |
|
Lancaster City PWS Fairfield County |
40,400 | 1 | 1 | |
|
Western Water Company Warren County |
39,508 | 1 | 1 | |
|
Westerville City PWS Franklin County |
39,000 | 0 | 0 | |
|
Reynoldsburg City PWS Franklin County |
37,847 | 1 | 1 | |
|
North Ridgeville City PWS Lorain County |
37,786 | 2 | 1 | |
|
Stow Public Water System Summit County |
35,437 | 2 | 1 | |
|
Ross County Water CO INC Ross County |
35,345 | 0 | 0 | |
|
Hecla Water Association Lawrence County |
34,942 | 0 | 0 | |
|
Fairborn Public Water System Greene County |
34,620 | 1 | 0 | |
|
Gahanna City PWS Franklin County |
33,258 | 1 | 0 |
About this data
Rules violated counts the rules a system was in violation of in the past three years, including monitoring and reporting lapses; one rule can carry several violations. Unresolved is the number of those rules still in violation at EPA's latest data refresh.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Ohio records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.