Public water system · WA5311914
ActiveCedar Grove
At a glance
Cedar Grove (PWSID WA5311914) is an active community water system in Mason County, Washington. It reports serving 156 people through 59 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in July 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
156
Service connections
59
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Cedar Grove compare with other water systems in Mason County?
By EPA's size categories, Cedar Grove is a very small system (500 people or fewer). Mason County has 240 active public water systems. Its population served is about half of the county average of 315 people per system, and accounts for 0.2% of the 75,633 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 Cedar Grove 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. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 4,370 Washington systems (93%) list groundwater as their primary source.
Who owns and regulates Cedar Grove?
EPA lists Cedar Grove as privately owned. 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. 163 of the 240 active systems in Mason County (68%) are also privately owned.
Does Cedar Grove have drinking water violations?
EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in July 2020. The violations listed here began between October 1979 and July 2020. By type: 4 contaminant level above the legal limit, 1 public notice, recordkeeping or other and 1 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 5 as archived and 1 as resolved. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status. 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 |
|---|---|---|---|---|
| 2020-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 1996-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1996-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1993-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1993-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
All 6 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.
Cedar Grove: frequently asked questions
Who runs Cedar Grove?
Cedar Grove (PWSID WA5311914) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Cedar Grove serve?
Cedar Grove reports serving 156 people through 59 service connections in Mason County, Washington.
Where does Cedar Grove 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 Cedar Grove have any drinking water violations?
EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in July 2020. 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 Cedar Grove'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. EPA's records list 6 violations for this system; 4 are health-based, and the most recent began in July 2020. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Cedar Grove's water quality report?
As a community water system, Cedar Grove 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 Mason County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Shelton City of | Mason | 15,089 | Community | Groundwater |
| Belfair Water District 1 | Mason | 4,432 | Community | Groundwater |
| Lake Cushman System 5 | Mason | 3,675 | Community | Groundwater |
| Twanoh State Park | Mason | 3,173 | Transient non-community | Groundwater |
| Belfair State Park | Mason | 2,411 | Transient non-community | Groundwater |
| Timberlake Community Club Inc. | Mason | 2,337 | 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, “Cedar Grove, PWSID WA5311914, Washington”, https://aquacensus.com/water-systems/washington/cedar-grove-wa5311914 (data as of October 1, 2026).