Public water system · WA5388050
ActiveThornton Water Association
At a glance
Thornton Water Association (PWSID WA5388050) is an active community water system in Whatcom County, Washington. It reports serving 55 people through 16 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, 4 are health-based, and the most recent began in September 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
55
Service connections
16
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Thornton Water Association compare with other water systems in Whatcom County?
By EPA's size categories, Thornton Water Association is a very small system (500 people or fewer). Whatcom County has 183 active public water systems. Its population served is well below the county average of 1,437 people per system, and accounts for less than 0.1% of the 263,011 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 Thornton 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 Thornton Water Association?
EPA lists Thornton 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. 140 of the 183 active systems in Whatcom County (77%) are also privately owned.
Does Thornton Water Association have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in September 2025. The violations listed here began between October 1979 and September 2025. By type: 7 monitoring and reporting, 4 contaminant level above the legal limit and 1 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (7 of them). EPA lists 11 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 |
|---|---|---|---|---|
| 2025-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2003-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1996-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1996-03-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 1995-09-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1992-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1992-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Mercurycode 1035 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Archived |
| 1979-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Cadmiumcode 1015 | 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.
Thornton Water Association: frequently asked questions
Who runs Thornton Water Association?
Thornton Water Association (PWSID WA5388050) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Thornton Water Association serve?
Thornton Water Association reports serving 55 people through 16 service connections in Whatcom County, Washington.
Where does Thornton 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 Thornton Water Association have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in September 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 Thornton 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, 4 are health-based, and the most recent began in September 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Thornton Water Association's water quality report?
As a community water system, Thornton 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 Whatcom County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Bellingham-Water Division City of | Whatcom | 141,127 | Community | Surface water |
| Lynden Water Department | Whatcom | 20,062 | Community | Surface water |
| Ferndale | Whatcom | 19,305 | Community | Groundwater |
| Lwwsd - South Shore Water System | Whatcom | 10,028 | Community | Surface water |
| Birch Bay Water & Sewer District | Whatcom | 9,046 | Community | Purchased groundwater |
| Blaine City of | Whatcom | 6,319 | 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, “Thornton Water Association, PWSID WA5388050, Washington”, https://aquacensus.com/water-systems/washington/thornton-water-association-wa5388050 (data as of October 1, 2026).