Public water system · CO0101170

Active

Westminster City of

At a glance

City of Westminster (PWSID CO0101170) is an active community water system in Adams County, Colorado. It reports serving 202,078 people through 33,619 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's records list 10 violations for this system; none is health-based, and the most recent began in January 2025.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

202,078

Service connections

33,619

Primary source

Surface water

System type

CWS

Community water system

System record

PWSIDCO0101170

System typeCommunity water system

Activity statusActive

Population served202,078

Service connections33,619

Primary water sourceSurface water

Owner typeLocal government

Primacy agencyCO state drinking water program

City served—

StateColorado

ZIP—

CountyAdams County

How does City of Westminster compare with other water systems in Adams County?

By EPA's size categories, City of Westminster is a very large system (more than 100,000 people). Adams County has 82 active public water systems, and City of Westminster is the 2nd-largest of them by population served. Its population served is about 23 times the county average of 8,669 people per system, and accounts for 28% of the 710,822 people reported by systems filed under the county. Across Colorado, the 2,207 active systems average 3,400 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Westminster is about 30 times 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. Colorado has 1,068 active community water systems, 48% of the state's 2,207 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 228 Colorado systems (10%) list surface water as their primary source.

Who owns and regulates City of Westminster?

EPA lists City of Westminster as owned by a local government. The CO state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 19 of the 82 active systems in Adams County (23%) are also owned by a local government.

Does City of Westminster have drinking water violations?

EPA's records list 10 violations for this system; none is health-based, and the most recent began in January 2025. The violations listed here began between January 1988 and January 2025. By type: 10 monitoring and reporting. The contaminant or rule involved most often is Surface Water Treatment Rule (3 of them). EPA lists 10 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
2025-01-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2024-12-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
2022-01-01	Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36	Surface Water Treatment Rulecode 0200	No	Resolved
1988-01-01	Monitoring and reportingMonitoring, Regular · code 03	Trichloroethylenecode 2984	No	Resolved
1988-01-01	Monitoring and reportingMonitoring, Regular · code 03	p-Dichlorobenzenecode 2969	No	Resolved
1988-01-01	Monitoring and reportingMonitoring, Regular · code 03	Benzenecode 2990	No	Resolved
1988-01-01	Monitoring and reportingMonitoring, Regular · code 03	1,2-Dichloroethanecode 2980	No	Resolved
1988-01-01	Monitoring and reportingMonitoring, Regular · code 03	Carbon tetrachloridecode 2982	No	Resolved
1988-01-01	Monitoring and reportingMonitoring, Regular · code 03	1,1-Dichloroethylenecode 2977	No	Resolved
1988-01-01	Monitoring and reportingMonitoring, Regular · code 03	1,1,1-Trichloroethanecode 2981	No	Resolved

All 10 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 Westminster: frequently asked questions

Who runs City of Westminster?

City of Westminster (PWSID CO0101170) is a community water system owned by a local government. It is regulated by the CO state drinking water program.

How many people does City of Westminster serve?

City of Westminster reports serving 202,078 people through 33,619 service connections in Adams County, Colorado.

Where does City of Westminster 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 Westminster have any drinking water violations?

EPA's records list 10 violations for this system; none is health-based, and the most recent began in January 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 Westminster'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 10 violations for this system; none is health-based, and the most recent began in January 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the CO state drinking water program.

Where can I find City of Westminster's water quality report?

As a community water system, City of Westminster 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 Adams County

Water system	County	Population served	Type	Source
Thornton City of	Adams	226,465	Community	Surface water
South Adams County Wsd	Adams	75,559	Community	Purchased surface water
Brighton City of	Adams	56,304	Community	Purchased surface water
Northglenn City of	Adams	48,927	Community	Surface water
Crestview Wsd	Adams	23,756	Community	Purchased surface water
North Washington Street Wsd	Adams	14,500	Community	Purchased surface water

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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, “Westminster City of, PWSID CO0101170, Colorado”, https://aquacensus.com/water-systems/colorado/westminster-city-of-co0101170 (data as of October 1, 2026).