Public water system · WA5315050
ActiveCosmopolis Water Department
At a glance
Cosmopolis Water Department (PWSID WA5315050) is an active community water system in Grays Harbor County, Washington. It reports serving 1,812 people through 783 service connections. Its primary water source is purchased 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 July 2023.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,812
Service connections
783
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Cosmopolis Water Department compare with other water systems in Grays Harbor County?
By EPA's size categories, Cosmopolis Water Department is a small system (501 to 3,300 people). Grays Harbor County has 88 active public water systems. Its population served is about 79% above the county average of 1,013 people per system, and accounts for 2% of the 89,150 people reported by systems filed under the county. Across Washington, the 4,705 active systems average 2,172 people each. Nationally, the average active community water system reports serving 6,703 people, so Cosmopolis Water Department 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. Washington has 2,392 active community water systems, 51% of the state's 4,705 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 130 Washington systems (2.8%) list purchased surface water as their primary source.
Who owns and regulates Cosmopolis Water Department?
EPA lists Cosmopolis Water Department as owned by a local government. The WA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 21 of the 88 active systems in Grays Harbor County (24%) are also owned by a local government.
Does Cosmopolis Water Department 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 2023. The violations listed here began between July 2018 and July 2023. By type: 10 monitoring and reporting and 2 public notice, recordkeeping or other. The contaminant or rule involved most often is Haloacetic acids (HAA5) (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 |
|---|---|---|---|---|
| 2023-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2021-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2019-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2019-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2019-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2019-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2019-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2019-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2019-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2018-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | 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.
Cosmopolis Water Department: frequently asked questions
Who runs Cosmopolis Water Department?
Cosmopolis Water Department (PWSID WA5315050) is a community water system owned by a local government. It is regulated by the WA state drinking water program.
How many people does Cosmopolis Water Department serve?
Cosmopolis Water Department reports serving 1,812 people through 783 service connections in Grays Harbor County, Washington.
Where does Cosmopolis Water Department get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Cosmopolis Water Department 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 2023. 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 Cosmopolis Water Department'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 2023. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Cosmopolis Water Department's water quality report?
As a community water system, Cosmopolis Water Department 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 Grays Harbor County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Aberdeen City of | Grays Harbor | 22,867 | Community | Surface water |
| Hoquiam Water Department | Grays Harbor | 11,456 | Community | Surface water |
| Ocean Shores Water Dept | Grays Harbor | 9,347 | Community | Groundwater |
| Elma City of | Grays Harbor | 6,638 | Community | Groundwater |
| Montesano City of | Grays Harbor | 6,204 | Community | Groundwater |
| Westport Water Department | Grays Harbor | 5,346 | 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, “Cosmopolis Water Department, PWSID WA5315050, Washington”, https://aquacensus.com/water-systems/washington/cosmopolis-water-department-wa5315050 (data as of October 1, 2026).