Public water system · ID4010133
ActiveSierra Water Corp
At a glance
Sierra Water Corp (PWSID ID4010133) is an active community water system in Ada County, Idaho. It reports serving 70 people through 22 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, none is health-based, and the most recent began in June 2019.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
70
Service connections
22
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Sierra Water Corp compare with other water systems in Ada County?
By EPA's size categories, Sierra Water Corp is a very small system (500 people or fewer). Ada County has 87 active public water systems. Its population served is well below the county average of 5,880 people per system, and accounts for less than 0.1% of the 511,514 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 Sierra Water Corp 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 Sierra Water Corp?
EPA lists Sierra Water Corp as privately owned. 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. 71 of the 87 active systems in Ada County (82%) are also privately owned.
Does Sierra Water Corp have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in June 2019. The violations listed here began between January 1996 and June 2019. By type: 10 monitoring and reporting and 2 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (6 of them). EPA lists 6 as resolved and 6 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 |
|---|---|---|---|---|
| 2019-06-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2017-10-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2008-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2007-03-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2006-03-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2005-03-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2002-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2001-07-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 2001-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Resolved |
| 1996-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,1-Trichloroethanecode 2981 | No | 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.
Sierra Water Corp: frequently asked questions
Who runs Sierra Water Corp?
Sierra Water Corp (PWSID ID4010133) is a community water system privately owned. It is regulated by the ID state drinking water program.
How many people does Sierra Water Corp serve?
Sierra Water Corp reports serving 70 people through 22 service connections in Ada County, Idaho.
Where does Sierra Water Corp 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 Sierra Water Corp have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in June 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 Sierra Water Corp'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, none is health-based, and the most recent began in June 2019. For current results, consult the system's annual water quality report, EPA ECHO, or the ID state drinking water program.
Where can I find Sierra Water Corp's water quality report?
As a community water system, Sierra Water Corp 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 Ada County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Veolia Water Idaho | Ada | 264,978 | Community | Surface water |
| Meridian Water Dept | Ada | 147,340 | Community | Groundwater |
| Kuna City of | Ada | 32,038 | Community | Groundwater |
| Star Sewer and Water Dist Water System | Ada | 14,000 | Community | Groundwater |
| Garden City Water and Sewer System | Ada | 12,500 | Community | Groundwater |
| Capitol Water Corp | Ada | 9,000 | 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, “Sierra Water Corp, PWSID ID4010133, Idaho”, https://aquacensus.com/water-systems/idaho/sierra-water-corp-id4010133 (data as of October 1, 2026).