Public water system · WA5330050
ActiveGrotto Water Association
At a glance
Grotto Water Association (PWSID WA5330050) is an active community water system in King County, Washington. It reports serving 36 people through 26 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, one is health-based, and the most recent began in July 2017.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
36
Service connections
26
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Grotto Water Association compare with other water systems in King County?
By EPA's size categories, Grotto Water Association is a very small system (500 people or fewer). King County has 214 active public water systems. Its population served is well below the county average of 15,523 people per system, and accounts for less than 0.1% of the 3,321,960 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 Grotto Water Association 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 Grotto Water Association?
EPA lists Grotto Water Association 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. 142 of the 214 active systems in King County (66%) are also privately owned.
Does Grotto Water Association have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2017. The violations listed here began between May 1997 and July 2017. By type: 9 monitoring and reporting, 2 public notice, recordkeeping or other and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (8 of them). EPA lists 7 as archived and 5 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 |
|---|---|---|---|---|
| 2017-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2013-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2010-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2004-10-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2004-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2000-05-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1998-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1998-04-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1998-03-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1998-01-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1997-05-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
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.
Grotto Water Association: frequently asked questions
Who runs Grotto Water Association?
Grotto Water Association (PWSID WA5330050) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Grotto Water Association serve?
Grotto Water Association reports serving 36 people through 26 service connections in King County, Washington.
Where does Grotto Water Association 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 Grotto Water Association have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in July 2017. 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 Grotto Water Association'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, one is health-based, and the most recent began in July 2017. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Grotto Water Association's water quality report?
As a community water system, Grotto Water Association 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 King County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Seattle Public Utilities | King | 1,161,961 | Community | Surface water |
| Bellevue City of | King | 321,349 | Community | Purchased surface water |
| Kent Water Department | King | 166,421 | Community | Purchased surface water |
| Redmond Water System City of | King | 163,335 | Community | Purchased surface water |
| Lakehaven Water and Sewer District | King | 148,809 | Community | Purchased surface water |
| Renton City of | King | 108,091 | 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, “Grotto Water Association, PWSID WA5330050, Washington”, https://aquacensus.com/water-systems/washington/grotto-water-association-wa5330050 (data as of October 1, 2026).