Public water system · ID7190032
ActiveMackay City of
At a glance
City of Mackay (PWSID ID7190032) is an active community water system in Custer County, Idaho. It reports serving 566 people through 400 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in January 2018.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
566
Service connections
400
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Mackay compare with other water systems in Custer County?
By EPA's size categories, City of Mackay is a small system (501 to 3,300 people). Custer County has 57 active public water systems, and City of Mackay is the 2nd-largest of them by population served. Its population served is about 5.5 times the county average of 102 people per system, and accounts for 9.7% of the 5,823 people reported by systems filed under the county. Across Idaho, the 1,961 active systems average 899 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Mackay 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. Idaho has 765 active community water systems, 39% of the state's 1,961 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,861 Idaho systems (95%) list groundwater as their primary source.
Who owns and regulates City of Mackay?
EPA lists City of Mackay as owned by a local government. The ID state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 4 of the 57 active systems in Custer County (7%) are also owned by a local government.
Does City of Mackay have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in January 2018. The violations listed here began between October 2003 and January 2018. By type: 9 monitoring and reporting and 3 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 8 as archived and 4 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 |
|---|---|---|---|---|
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Uraniumcode 4006 | No | Archived |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Archived |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Radium-226code 4020 | No | Archived |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Radium-228code 4030 | No | Archived |
| 2013-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2012-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2010-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2005-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Archived |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Atrazinecode 2050 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Atrazinecode 2050 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Atrazinecode 2050 | No | Resolved |
| 2003-10-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | 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.
City of Mackay: frequently asked questions
Who runs City of Mackay?
City of Mackay (PWSID ID7190032) is a community water system owned by a local government. It is regulated by the ID state drinking water program.
How many people does City of Mackay serve?
City of Mackay reports serving 566 people through 400 service connections in Custer County, Idaho.
Where does City of Mackay 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 City of Mackay have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in January 2018. 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 Mackay'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, 3 are health-based, and the most recent began in January 2018. For current results, consult the system's annual water quality report, EPA ECHO, or the ID state drinking water program.
Where can I find City of Mackay's water quality report?
As a community water system, City of Mackay 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 Custer County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Challis City of | Custer | 900 | Community | Surface water |
| Blm Joe T Fallini | Custer | 540 | Transient non-community | Groundwater |
| Usfs Fishook Well | Custer | 460 | Transient non-community | Groundwater |
| Usfs Glacier View Campground | Custer | 314 | Transient non-community | Groundwater |
| Mountain Village Lodge and Restaurant | Custer | 225 | Transient non-community | Groundwater |
| Sawtooth Luces | Custer | 200 | Transient non-community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Mackay City of, PWSID ID7190032, Idaho”, https://aquacensus.com/water-systems/idaho/mackay-city-of-id7190032 (data as of October 1, 2026).