Public water system · OH5400312
ActiveGrand Lake Estates
At a glance
Grand Lake Estates (PWSID OH5400312) is an active community water system in Mercer County, Ohio. It reports serving 103 people through 68 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
103
Service connections
68
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Grand Lake Estates compare with other water systems in Mercer County?
By EPA's size categories, Grand Lake Estates is a very small system (500 people or fewer). Mercer County has 77 active public water systems. Its population served is well below the county average of 397 people per system, and accounts for 0.3% of the 30,601 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 Grand Lake Estates is well below 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 Grand Lake Estates?
EPA lists Grand Lake Estates as privately owned. 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. 69 of the 77 active systems in Mercer County (90%) are also privately owned.
Does Grand Lake Estates have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2026. The violations listed here began between January 2016 and January 2026. By type: 8 public notice, recordkeeping or other, 2 required treatment not met, 1 monitoring and 1 monitoring and reporting. The contaminant or rule involved most often is Consumer Confidence Rule (8 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 |
|---|---|---|---|---|
| 2026-01-23 | Required treatment not metTreatment Technique No Certif. Operator · code 12 | Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400 | Yes | Resolved |
| 2026-01-20 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Unaddressed |
| 2025-12-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2024-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2023-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2022-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2021-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2020-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2018-11-14 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2016-02-03 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2016-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | 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.
Grand Lake Estates: frequently asked questions
Who runs Grand Lake Estates?
Grand Lake Estates (PWSID OH5400312) is a community water system privately owned. It is regulated by the OH state drinking water program.
How many people does Grand Lake Estates serve?
Grand Lake Estates reports serving 103 people through 68 service connections in Mercer County, Ohio.
Where does Grand Lake Estates 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 Grand Lake Estates have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2026. 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 Grand Lake Estates' 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, 2 are health-based, and the most recent began in January 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the OH state drinking water program.
Where can I find Grand Lake Estates' water quality report?
As a community water system, Grand Lake Estates 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 Mercer County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Celina, City of | Mercer | 11,682 | Community | Surface water |
| Coldwater Village | Mercer | 4,774 | Community | Groundwater |
| St Henry Village | Mercer | 2,596 | Community | Groundwater |
| Ft Recovery Village | Mercer | 1,501 | Community | Groundwater |
| Rockford Village | Mercer | 1,120 | Community | Groundwater |
| Mendon Village | Mercer | 628 | Community | Groundwater |
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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, “Grand Lake Estates, PWSID OH5400312, Ohio”, https://aquacensus.com/water-systems/ohio/grand-lake-estates-oh5400312 (data as of October 1, 2026).