Public water system · OR4100546
ActiveMount Vernon, City of
At a glance
City of Mount Vernon (PWSID OR4100546) is an active community water system in Grant County, Oregon. It reports serving 510 people through 273 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, 3 are health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
510
Service connections
273
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Mount Vernon compare with other water systems in Grant County?
By EPA's size categories, City of Mount Vernon is a small system (501 to 3,300 people). Grant County has 15 active public water systems, and City of Mount Vernon is the 4th-largest of them by population served. Its population served is about 50% above the county average of 339 people per system, and accounts for 10% of the 5,090 people reported by systems filed under the county. Across Oregon, the 2,536 active systems average 1,587 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Mount Vernon 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. Oregon has 940 active community water systems, 37% of the state's 2,536 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,175 Oregon systems (86%) list groundwater as their primary source.
Who owns and regulates City of Mount Vernon?
EPA lists City of Mount Vernon as owned by a local government. The OR state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 8 of the 15 active systems in Grant County (53%) are also owned by a local government.
Does City of Mount Vernon have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in July 2025. The violations listed here began between January 2002 and July 2025. By type: 7 monitoring and reporting, 2 public notice, recordkeeping or other, 2 contaminant level above the legal limit and 1 required treatment not met. The contaminant or rule involved most often is Total coliform bacteria (TCR) (5 of them). EPA lists 12 as resolved. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-12-24 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2007-11-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2006-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Hexachlorobenzenecode 2274 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Polychlorinated biphenyls (PCBs), totalcode 2383 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Methoxychlorcode 2015 | No | Resolved |
| 2003-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2002-01-02 | Required treatment not metOCCT/SOWT Treatment Installation/Demonstration · code 58 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1-Dichloroethylenecode 2977 | 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.
City of Mount Vernon: frequently asked questions
Who runs City of Mount Vernon?
City of Mount Vernon (PWSID OR4100546) is a community water system owned by a local government. It is regulated by the OR state drinking water program.
How many people does City of Mount Vernon serve?
City of Mount Vernon reports serving 510 people through 273 service connections in Grant County, Oregon.
Where does City of Mount Vernon 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 City of Mount Vernon have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are 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 City of Mount Vernon'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, 3 are 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 OR state drinking water program.
Where can I find City of Mount Vernon's water quality report?
As a community water system, City of Mount Vernon 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 Grant County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| John Day, City of | Grant | 1,617 | Community | Groundwater |
| Prairie City | Grant | 841 | Community | Groundwater under influence of surface water |
| Canyon City Water Department | Grant | 666 | Community | Groundwater under influence of surface water |
| Oprd Clyde Holliday Wayside | Grant | 450 | Transient non-community | Groundwater |
| Seneca, City of | Grant | 200 | Community | Groundwater |
| Long Creek, City of | Grant | 173 | 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, “Mount Vernon, City of, PWSID OR4100546, Oregon”, https://aquacensus.com/water-systems/oregon/mount-vernon-city-of-or4100546 (data as of October 1, 2026).