Public water system · MT0000525

Active

Great Falls City of

At a glance

City of Great Falls (PWSID MT0000525) is an active community water system in Cascade County, Montana. It reports serving 60,000 people through 22,477 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. EPA's records list 9 violations for this system; 6 are health-based, and the most recent began in April 2019.

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

Population served

60,000

Service connections

22,477

Primary source

Surface water

System type

CWS

Community water system

System record

PWSIDMT0000525

System typeCommunity water system

Activity statusActive

Population served60,000

Service connections22,477

Primary water sourceSurface water

Owner typeLocal government

Primacy agencyMT state drinking water program

City servedGreat Falls

StateMontana

ZIP—

CountyCascade County

How does City of Great Falls compare with other water systems in Cascade County?

By EPA's size categories, City of Great Falls is a large system (10,001 to 100,000 people). Cascade County has 98 active public water systems, and City of Great Falls is the largest of them by population served. Its population served is about 61 times the county average of 985 people per system, and accounts for 62% of the 96,513 people reported by systems filed under the county. Across Montana, the 2,378 active systems average 489 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Great Falls is about 9 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. Montana has 853 active community water systems, 36% of the state's 2,378 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 60 Montana systems (2.5%) list surface water as their primary source.

Who owns and regulates City of Great Falls?

EPA lists City of Great Falls as owned by a local government. The MT state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 14 of the 98 active systems in Cascade County (14%) are also owned by a local government.

Does City of Great Falls have drinking water violations?

EPA's records list 9 violations for this system; 6 are health-based, and the most recent began in April 2019. The violations listed here began between August 1997 and April 2019. By type: 5 contaminant level above the legal limit, 3 monitoring and reporting and 1 required treatment not met. The contaminant or rule involved most often is Haloacetic acids (HAA5) (6 of them). EPA lists 8 as resolved and 1 as archived. 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. 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.

Began	Violation	Contaminant or rule	Health-based	Status
2019-04-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Haloacetic acids (HAA5)code 2456	Yes	Resolved
2019-01-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Haloacetic acids (HAA5)code 2456	Yes	Resolved
2018-10-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Haloacetic acids (HAA5)code 2456	Yes	Resolved
2018-07-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Haloacetic acids (HAA5)code 2456	Yes	Resolved
2018-04-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Haloacetic acids (HAA5)code 2456	Yes	Resolved
2006-10-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Haloacetic acids (HAA5)code 2456	No	Resolved
2006-10-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Total trihalomethanes (TTHM)code 2950	No	Resolved
2002-01-01	Monitoring and reportingMonitoring, Regular · code 03	Asbestoscode 1094	No	Archived
1997-08-01	Required treatment not metTreatment Technique (SWTR and GWR) · code 41	Surface Water Treatment Rulecode 0200	Yes	Resolved

All 9 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 Great Falls: frequently asked questions

Who runs City of Great Falls?

City of Great Falls (PWSID MT0000525) is a community water system owned by a local government. It is regulated by the MT state drinking water program.

How many people does City of Great Falls serve?

City of Great Falls reports serving 60,000 people through 22,477 service connections in Cascade County, Montana.

Where does City of Great Falls 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 Great Falls have any drinking water violations?

EPA's records list 9 violations for this system; 6 are health-based, and the most recent began in April 2019. 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 Great Falls' 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 9 violations for this system; 6 are health-based, and the most recent began in April 2019. For current results, consult the system's annual water quality report, EPA ECHO, or the MT state drinking water program.

Where can I find City of Great Falls' water quality report?

As a community water system, City of Great Falls 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 Cascade County

Water system	County	Population served	Type	Source
Malmstrom Air Force Base	Cascade	8,850	Community	Purchased surface water
Source Giant Springs Inc.	Cascade	3,007	Non-transient non-community	Groundwater
Montana Expo Park Cascade County	Cascade	2,510	Transient non-community	Purchased surface water
Sun Prairie Village County	Cascade	1,800	Community	Groundwater
University of Providence	Cascade	1,472	Non-transient non-community	Purchased surface water
Black Eagle Cascade County Water Sewer	Cascade	1,233	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, “Great Falls City of, PWSID MT0000525, Montana”, https://aquacensus.com/water-systems/montana/great-falls-city-of-mt0000525 (data as of October 1, 2026).