Public water system · CA4710008
ActiveMt. Shasta, City of
At a glance
City of Mt. Shasta (PWSID CA4710008) is an active community water system in Siskiyou County, California. It reports serving 3,642 people through 1,884 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, 11 are health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
3,642
Service connections
1,884
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Mt. Shasta compare with other water systems in Siskiyou County?
By EPA's size categories, City of Mt. Shasta is a medium system (3,301 to 10,000 people). Siskiyou County has 69 active public water systems, and City of Mt. Shasta is the 2nd-largest of them by population served. Its population served is about 6.1 times the county average of 593 people per system, and accounts for 8.9% of the 40,908 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Mt. Shasta is about half of 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. California has 2,997 active community water systems, 40% of the state's 7,479 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 6,179 California systems (83%) list groundwater as their primary source.
Who owns and regulates City of Mt. Shasta?
EPA lists City of Mt. Shasta as owned by a local government. The CA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 21 of the 69 active systems in Siskiyou County (30%) are also owned by a local government.
Does City of Mt. Shasta have drinking water violations?
Of the 12 most recent violations in EPA's records, 11 are health-based, and the most recent began in October 2024. The violations listed here began between August 2014 and October 2024. By type: 9 contaminant level above the legal limit, 2 required treatment not met and 1 reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (6 of them). EPA lists 10 as resolved and 2 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Unaddressed |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2019-09-01 | Required treatment not metTreatment Technique, Level 1 Assessment (RTCR) · code 2A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2017-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2017-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2017-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2016-03-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2015-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2015-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2014-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2014-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
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 Mt. Shasta: frequently asked questions
Who runs City of Mt. Shasta?
City of Mt. Shasta (PWSID CA4710008) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does City of Mt. Shasta serve?
City of Mt. Shasta reports serving 3,642 people through 1,884 service connections in Siskiyou County, California.
Where does City of Mt. Shasta 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 Mt. Shasta have any drinking water violations?
Of the 12 most recent violations in EPA's records, 11 are health-based, and the most recent began in October 2024. 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 Mt. Shasta'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, 11 are health-based, and the most recent began in October 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find City of Mt. Shasta's water quality report?
As a community water system, City of Mt. Shasta 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 Siskiyou County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Yreka, City of | Siskiyou | 7,825 | Community | Surface water |
| Mt. Shasta Ski Park | Siskiyou | 3,500 | Transient non-community | Groundwater |
| Lake Shastina C.S.D | Siskiyou | 2,790 | Community | Groundwater |
| Weed, City of | Siskiyou | 2,662 | Community | Groundwater |
| Lake Siskiyou Campground | Siskiyou | 1,800 | Transient non-community | Surface water |
| Dunsmuir, City of | Siskiyou | 1,707 | 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, “Mt. Shasta, City of, PWSID CA4710008, California”, https://aquacensus.com/water-systems/california/mt-shasta-city-of-ca4710008 (data as of October 1, 2026).