Public water system · OR4100372
ActiveHermiston, City of
At a glance
City of Hermiston (PWSID OR4100372) is an active community water system in Umatilla County, Oregon. It reports serving 20,000 people through 5,979 service connections. Its primary water source is surface water, 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 February 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
20,000
Service connections
5,979
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does City of Hermiston compare with other water systems in Umatilla County?
By EPA's size categories, City of Hermiston is a large system (10,001 to 100,000 people). Umatilla County has 66 active public water systems, and City of Hermiston is the largest of them by population served. Its population served is about 19 times the county average of 1,041 people per system, and accounts for 29% of the 68,687 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 Hermiston is about 198% above 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. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 211 Oregon systems (8.3%) list surface water as their primary source.
Who owns and regulates City of Hermiston?
EPA lists City of Hermiston 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. 17 of the 66 active systems in Umatilla County (26%) are also owned by a local government.
Does City of Hermiston have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in February 2025. The violations listed here began between April 2014 and February 2025. By type: 11 monitoring and reporting and 1 monitoring. The contaminant or rule involved most often is Coliphage (4 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 |
|---|---|---|---|---|
| 2025-02-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2022-09-01 | Monitoring and reportingFailure to Conduct Assessment Monitoring · code 19 | Coliphagecode 3028 | No | Resolved |
| 2022-09-01 | Monitoring and reportingFailure to Conduct Assessment Monitoring · code 19 | Coliphagecode 3028 | No | Resolved |
| 2022-07-01 | Monitoring and reportingFailure to Conduct Assessment Monitoring · code 19 | Coliphagecode 3028 | No | Resolved |
| 2022-07-01 | Monitoring and reportingFailure to Conduct Assessment Monitoring · code 19 | Coliphagecode 3028 | No | Resolved |
| 2016-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2016-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2015-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2015-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2014-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2014-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | 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 Hermiston: frequently asked questions
Who runs City of Hermiston?
City of Hermiston (PWSID OR4100372) 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 Hermiston serve?
City of Hermiston reports serving 20,000 people through 5,979 service connections in Umatilla County, Oregon.
Where does City of Hermiston get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does City of Hermiston 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 February 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 Hermiston'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 February 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 Hermiston's water quality report?
As a community water system, City of Hermiston 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 Umatilla County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Pendleton, City of | Umatilla | 16,996 | Community | Surface water |
| Umatilla, City of | Umatilla | 8,256 | Community | Groundwater |
| Milton-Freewater, City of | Umatilla | 7,145 | Community | Groundwater |
| Stanfield, City of | Umatilla | 2,115 | Community | Groundwater |
| Pilot Rock, City of | Umatilla | 1,326 | Community | Groundwater |
| Athena, City of | Umatilla | 1,238 | 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, “Hermiston, City of, PWSID OR4100372, Oregon”, https://aquacensus.com/water-systems/oregon/hermiston-city-of-or4100372 (data as of October 1, 2026).