Public water system · ID4010022
ActiveCapitol Water Corp
At a glance
Capitol Water Corp (PWSID ID4010022) is an active community water system in Ada County, Idaho. It reports serving 9,000 people through 2,811 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 October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
9,000
Service connections
2,811
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Capitol Water Corp compare with other water systems in Ada County?
By EPA's size categories, Capitol Water Corp is a medium system (3,301 to 10,000 people). Ada County has 87 active public water systems, and Capitol Water Corp is the 6th-largest of them by population served. Its population served is about 53% above the county average of 5,880 people per system, and accounts for 1.8% 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 Capitol Water Corp is about 34% above 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 Capitol Water Corp?
EPA lists Capitol 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 Capitol 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 October 2025. The violations listed here began between October 2025 and October 2025. By type: 12 monitoring and reporting. The contaminants or rules involved are cis-1,2-Dichloroethylene, Tetrachloroethylene, Trichloroethylene and 1,2-Dichloroethane. EPA lists 12 as archived. 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 |
|---|---|---|---|---|
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | cis-1,2-Dichloroethylenecode 2380 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Tetrachloroethylenecode 2987 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Trichloroethylenecode 2984 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloroethanecode 2980 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Ethylbenzenecode 2992 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Styrenecode 2996 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,2-Trichloroethanecode 2985 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloropropanecode 2983 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | o-Dichlorobenzenecode 2968 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,1-Trichloroethanecode 2981 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlorobenzenecode 2989 | No | Archived |
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Dichloromethanecode 2964 | 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.
Capitol Water Corp: frequently asked questions
Who runs Capitol Water Corp?
Capitol Water Corp (PWSID ID4010022) is a community water system privately owned. It is regulated by the ID state drinking water program.
How many people does Capitol Water Corp serve?
Capitol Water Corp reports serving 9,000 people through 2,811 service connections in Ada County, Idaho.
Where does Capitol 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 Capitol 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 October 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 Capitol 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 October 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the ID state drinking water program.
Where can I find Capitol Water Corp's water quality report?
As a community water system, Capitol 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 |
| Eagle, City of (Western Zone) | Ada | 6,108 | 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, “Capitol Water Corp, PWSID ID4010022, Idaho”, https://aquacensus.com/water-systems/idaho/capitol-water-corp-id4010022 (data as of October 1, 2026).