Public water system · OH7003512
ActiveOntario City
At a glance
Ontario City (PWSID OH7003512) is an active community water system in Richland County, Ohio. It reports serving 6,756 people through 2,769 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
6,756
Service connections
2,769
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Ontario City compare with other water systems in Richland County?
By EPA's size categories, Ontario City is a medium system (3,301 to 10,000 people). Richland County has 106 active public water systems, and Ontario City is the 3rd-largest of them by population served. Its population served is about 7.2 times the county average of 942 people per system, and accounts for 6.8% of the 99,812 people reported by systems filed under the county. Across Ohio, the 3,854 active systems average 2,767 people each. Nationally, the average active community water system reports serving 6,703 people, so Ontario City is roughly in line with that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Ohio has 1,028 active community water systems, 27% of the state's 3,854 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 3,446 Ohio systems (89%) list groundwater as their primary source.
Who owns and regulates Ontario City?
EPA lists Ontario City as owned by a local government. The OH state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 12 of the 106 active systems in Richland County (11%) are also owned by a local government.
Does Ontario City have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025. The violations listed here began between January 1995 and July 2025. By type: 9 monitoring and reporting, 2 public notice, recordkeeping or other and 1 reporting. The contaminant or rule involved most often is Consumer Confidence Rule (2 of them). EPA lists 11 as resolved and 1 as unaddressed. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-07-02 | ReportingNotification, Known or Potential LSL · code 4H | Lead and Copper Rule Revisionscode 5200 | No | Resolved |
| 2018-12-13 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Unaddressed |
| 2002-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 1999-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1995-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chromiumcode 1020 | No | Resolved |
| 1995-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Resolved |
| 1995-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Mercurycode 1035 | No | Resolved |
| 1995-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nickelcode 1036 | No | Resolved |
| 1995-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Seleniumcode 1045 | No | Resolved |
| 1995-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Resolved |
| 1995-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Cyanidecode 1024 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Ontario City: frequently asked questions
Who runs Ontario City?
Ontario City (PWSID OH7003512) is a community water system owned by a local government. It is regulated by the OH state drinking water program.
How many people does Ontario City serve?
Ontario City reports serving 6,756 people through 2,769 service connections in Richland County, Ohio.
Where does Ontario City get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Ontario City have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Ontario City's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the OH state drinking water program.
Where can I find Ontario City's water quality report?
As a community water system, Ontario City must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Richland County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Mansfield City | Richland | 51,000 | Community | Surface water |
| Shelby City | Richland | 9,453 | Community | Surface water |
| Lexington Village | Richland | 4,825 | Community | Groundwater |
| Madison Water District | Richland | 2,050 | Community | Groundwater |
| Bellville Village | Richland | 1,918 | Community | Groundwater |
| Plymouth Village | Richland | 1,874 | Community | Purchased surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Ontario City, PWSID OH7003512, Ohio”, https://aquacensus.com/water-systems/ohio/ontario-city-oh7003512 (data as of October 1, 2026).