Community Water System · PWS ID4010022
Capitol Water Corp
Boise, Idaho 83704 - drinking water served from groundwater sources to 9,000 people, tracked in EPA SDWIS and UCMR5.
- 9,000
- People served
- 113
- EPA violations
- 14
- Health-based
- 7 PFAS
- UCMR5 result
The verdict
EPA records 113 drinking-water violations at Capitol Water Corp, 12% of them health-based - above the Idaho per-system average, and UCMR5 testing detected 7 PFAS compounds.
- 113
- Total EPA violations on record
- 12%
- Health-based (MCL / treatment failure)
- 9,000
- People served by this system
- 7
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Capitol Water Corp
Capitol Water Corp is a private-owned community water system that delivers drinking water to 9,000 residents in Boise, Idaho (Ada County) through 2,811 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 113 total violations for this system , of which 14 (12%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 88 monitoring and reporting violations are on file. The most recent violation on record dates to 2025.
The most frequently cited contaminant at this system is Coliform (TCR), recorded in 30 violations (MR). Under EPA's UCMR5 PFAS monitoring program, 7 PFAS compounds were detected in samples collected from this system, with a maximum reported concentration of 51 ppt (parts per trillion). PFAS are persistent synthetic chemicals linked to health effects at very low exposure levels.
Across Idaho, EPA tracks 2,005 public water systems serving 1,743,912 people, with 104,850 cumulative violations and 19,965 health-based violations on record. About 96% of systems in the state carry at least one violation, and state-wide the average per system is 52.3 violations. Statewide, 40 of 60 UCMR5-tested systems have reported PFAS detections (66.7%).
Capitol Water Corp's 113 violations sit above the Idaho average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
7 PFAS "forever chemicals" detected in testing under EPA's UCMR5 monitoring program.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 2,811
- County
- Ada
- School/Daycare
- No
- MCL Violations
- 7
- Monitoring Violations
- 88
- Treatment Tech Violations
- 7
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 30 | 2015 |
| Nitrate | MR | 11 | 2009 |
| Lead and Copper Rule | MR | 11 | 2017 |
| Combined Uranium | MR | 9 | 2022 |
| Public Notice | Other | 5 | 2025 |
| Combined Uranium | MCL | 5 | 2025 |
| LEAD AND COPPER RULE REVISIONS | TT | 4 | 2024 |
| Groundwater Rule | TT | 3 | 2014 |
| Revised Total Coliform Rule | MON | 3 | 2019 |
| LEAD AND COPPER RULE REVISIONS | RPT | 3 | 2024 |
| Coliform (TCR) | MCL | 2 | 1998 |
| Benzene | MR | 1 | 1996 |
| Carbon tetrachloride | MR | 1 | 1996 |
| 1,1-Dichloroethylene | MR | 1 | 1996 |
| trans-1,2-Dichloroethylene | MR | 1 | 1996 |
| 1,2-Dichloroethane | MR | 1 | 1996 |
| p-Dichlorobenzene | MR | 1 | 1996 |
| Ethylbenzene | MR | 1 | 1996 |
| CHLOROBENZENE | MR | 1 | 1996 |
| Styrene | MR | 1 | 1996 |
| 1,1,1-Trichloroethane | MR | 1 | 1996 |
| Toluene | MR | 1 | 1996 |
| Picloram | MR | 1 | 1996 |
| 2,4,5-TP | MR | 1 | 1996 |
| Radium-226 | MR | 1 | 2008 |
| Dalapon | MR | 1 | 1996 |
| Trichloroethylene | MR | 1 | 1996 |
| Tetrachloroethylene | MR | 1 | 1996 |
| o-Dichlorobenzene | MR | 1 | 1996 |
| 1,2-Dichloropropane | MR | 1 | 1996 |
PFAS Testing Results (UCMR5)
Results from EPA's Fifth Unregulated Contaminant Monitoring Rule. 21 of 232 samples detected PFAS.
| Contaminant | Date | Result | MRL | Status |
|---|---|---|---|---|
| HFPO-DA | 8/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFMPA | 8/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxS | 8/8/2023 | 4.60 ppt | 3.00 ppt | Detected |
| PFNA | 8/8/2023 | 4.90 ppt | 4.00 ppt | Detected |
| PFOS | 8/8/2023 | 9.10 ppt | 4.00 ppt | Detected |
| PFOA | 8/8/2023 | 5.90 ppt | 4.00 ppt | Detected |
| PFDoA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 8/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 11Cl-PF3OUdS | 8/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| ADONA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBA | 8/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 6:2 FTS | 8/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFBS | 8/8/2023 | 4.00 ppt | 3.00 ppt | Detected |
| 8:2 FTS | 8/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| PFDA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeA | 8/8/2023 | 4.80 ppt | 3.00 ppt | Detected |
| PFPeS | 8/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFMBA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFEESA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NFDHA | 8/8/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFTA | 8/8/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFTrDA | 8/8/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| NEtFOSAA | 8/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| NMeFOSAA | 8/8/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| 9Cl-PF3ONS | 8/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| 4:2 FTS | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFHxA | 8/8/2023 | 4.60 ppt | 3.00 ppt | Detected |
| PFHxS | 8/8/2023 | 5.50 ppt | 3.00 ppt | Detected |
| PFHxA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDoA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFDA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFOA | 8/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFOS | 8/8/2023 | 4.10 ppt | 4.00 ppt | Detected |
| NEtFOSAA | 8/8/2023 | <5.00 ppt | 5.00 ppt | Not Detected |
| 9Cl-PF3ONS | 8/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFHpA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFBS | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| NMeFOSAA | 8/8/2023 | <6.00 ppt | 6.00 ppt | Not Detected |
| PFTrDA | 8/8/2023 | <7.00 ppt | 7.00 ppt | Not Detected |
| PFTA | 8/8/2023 | <8.00 ppt | 8.00 ppt | Not Detected |
| PFNA | 8/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFMPA | 8/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| PFHpS | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFPeS | 8/8/2023 | <4.00 ppt | 4.00 ppt | Not Detected |
| NFDHA | 8/8/2023 | <20.00 ppt | 20.00 ppt | Not Detected |
| PFEESA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
| PFUnA | 8/8/2023 | <2.00 ppt | 2.00 ppt | Not Detected |
| PFPeA | 8/8/2023 | <3.00 ppt | 3.00 ppt | Not Detected |
Verify This Water System
The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Capitol Water Corp.
EPA SDWIS, Federal Reports
EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:
View PWS ID ID4010022 on SDWISSource: EPA SDWIS Federal Reports Search
Idaho Drinking Water Authority
Idaho's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.
Find ID regulator via EPA SDWISViolation Timeline
Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.
| Year (latest) | Contaminant | Category | Count | EPA Record |
|---|---|---|---|---|
| 2025 | Public Notice | Other | 5 | SDWIS / ID4010022 / 7500 |
| 2025 | Combined Uranium | MCL | 5 | SDWIS / ID4010022 / 4006 |
| 2024 | LEAD AND COPPER RULE REVISIONS | TT | 4 | SDWIS / ID4010022 / 5200 |
| 2024 | LEAD AND COPPER RULE REVISIONS | RPT | 3 | SDWIS / ID4010022 / 5200 |
| 2022 | Combined Uranium | MR | 9 | SDWIS / ID4010022 / 4006 |
| 2019 | Revised Total Coliform Rule | MON | 3 | SDWIS / ID4010022 / 8000 |
| 2017 | Lead and Copper Rule | MR | 11 | SDWIS / ID4010022 / 5000 |
| 2015 | Coliform (TCR) | MR | 30 | SDWIS / ID4010022 / 3100 |
| 2014 | Groundwater Rule | TT | 3 | SDWIS / ID4010022 / 0700 |
| 2009 | Nitrate | MR | 11 | SDWIS / ID4010022 / 1040 |
| 2008 | Radium-226 | MR | 1 | SDWIS / ID4010022 / 4020 |
| 1999 | Arsenic | MR | 1 | SDWIS / ID4010022 / 1005 |
| 1998 | Coliform (TCR) | MCL | 2 | SDWIS / ID4010022 / 3100 |
| 1996 | Benzene | MR | 1 | SDWIS / ID4010022 / 2990 |
| 1996 | Carbon tetrachloride | MR | 1 | SDWIS / ID4010022 / 2982 |
How Capitol Water Corp Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Capitol Water Corp | Idaho avg | Federal benchmark |
|---|---|---|---|
| Total violations | 113 | 52.3 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 14 | 10 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | 7 compounds | 66.7% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 9,000 | 870 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,005 regulated public water systems in Idaho.
Federal MCL reference, Safe Drinking Water Act thresholds ▼
| Contaminant | Federal MCL / Action Level | Note |
|---|---|---|
| Lead | 0 mg/L (Action Level: 0.015 mg/L) | Lead and Copper Rule treatment technique |
| Arsenic | 0.010 mg/L (10 ppb) | Health-based MCL since 2006 |
| Total Coliform | Treatment technique (RTCR) | Indicator organism, monitoring trigger |
| PFOA / PFOS (PFAS) | 4.0 ppt each (final 2024 rule) | Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026) |
| Nitrate (as N) | 10 mg/L | Acute health risk for infants |
Frequently Asked Questions
Is Capitol Water Corp water safe to drink? ▼
How many people does Capitol Water Corp serve? ▼
What type of violations does Capitol Water Corp have? ▼
Has PFAS been detected in Capitol Water Corp water? ▼
What water source does Capitol Water Corp use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.