Community Water System · PWS NN0436006
Dilcon Community Boarding School BIA
Winslow, Navajo Nation 86047 - drinking water served from groundwater sources to 473 people, tracked in EPA SDWIS and UCMR5.
- 473
- People served
- 114
- EPA violations
- 30
- Health-based
- Untested
- UCMR5 result
The verdict
EPA records 114 drinking-water violations at Dilcon Community Boarding School BIA, 26% of them health-based - below the Navajo Nation per-system average.
- 114
- Total EPA violations on record
- 26%
- Health-based (MCL / treatment failure)
- 473
- People served by this system
- N/A
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Dilcon Community Boarding School BIA
Dilcon Community Boarding School BIA is a federal-owned community water system that delivers drinking water to 473 residents in Winslow, Navajo Nation through 60 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 114 total violations for this system , of which 30 (26%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 42 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 Arsenic, recorded in 30 violations (MCL, health-based). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.
Across Navajo Nation, EPA tracks 170 public water systems serving 167,275 people, with 29,535 cumulative violations and 1,366 health-based violations on record. About 100% of systems in the state carry at least one violation, and state-wide the average per system is 173.7 violations. Statewide, 13 of 13 UCMR5-tested systems have reported PFAS detections (100%).
Dilcon Community Boarding School BIA's 114 violations sit below the Navajo Nation average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
System Details
- System Type
- Community
- Owner Type
- Federal
- Connections
- 60
- School/Daycare
- Yes
- MCL Violations
- 30
- Monitoring Violations
- 42
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Arsenic | MCL | 30 | 2024 |
| Public Notice | Other | 13 | 2025 |
| Coliform (TCR) | MR | 12 | 2012 |
| Arsenic | MR | 9 | 2025 |
| Consumer Confidence Rule | Other | 4 | 2006 |
| 2,3,7,8-TCDD | MR | 4 | 2008 |
| Fluoride | MR | 4 | 2008 |
| Revised Total Coliform Rule | MON | 3 | 2025 |
| Revised Total Coliform Rule | RPT | 3 | 2023 |
| Revised Total Coliform Rule | Other | 3 | 2016 |
| CYANIDE | MR | 3 | 2008 |
| Stage 2 Disinfectants and Disinfection Byproducts Rule | MR | 3 | 2013 |
| Nitrate | MR | 1 | 2024 |
| Nitrite | MR | 1 | 2024 |
| Total Haloacetic Acids (HAA5) | MR | 1 | 2011 |
| Lead and Copper Rule | MR | 1 | 2004 |
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 Dilcon Community Boarding School BIA.
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 NN0436006 on SDWISSource: EPA SDWIS Federal Reports Search
Navajo Nation Drinking Water Authority
Navajo Nation'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 NN 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 | 13 | SDWIS / NN0436006 / 7500 |
| 2025 | Arsenic | MR | 9 | SDWIS / NN0436006 / 1005 |
| 2025 | Revised Total Coliform Rule | MON | 3 | SDWIS / NN0436006 / 8000 |
| 2024 | Arsenic | MCL | 30 | SDWIS / NN0436006 / 1005 |
| 2024 | Nitrate | MR | 1 | SDWIS / NN0436006 / 1040 |
| 2024 | Nitrite | MR | 1 | SDWIS / NN0436006 / 1041 |
| 2023 | Revised Total Coliform Rule | RPT | 3 | SDWIS / NN0436006 / 8000 |
| 2016 | Revised Total Coliform Rule | Other | 3 | SDWIS / NN0436006 / 8000 |
| 2013 | Stage 2 Disinfectants and Disinfection Byproducts Rule | MR | 3 | SDWIS / NN0436006 / 0600 |
| 2012 | Coliform (TCR) | MR | 12 | SDWIS / NN0436006 / 3100 |
| 2011 | Total Haloacetic Acids (HAA5) | MR | 1 | SDWIS / NN0436006 / 2456 |
| 2008 | 2,3,7,8-TCDD | MR | 4 | SDWIS / NN0436006 / 2063 |
| 2008 | Fluoride | MR | 4 | SDWIS / NN0436006 / 1025 |
| 2008 | CYANIDE | MR | 3 | SDWIS / NN0436006 / 1024 |
| 2006 | Consumer Confidence Rule | Other | 4 | SDWIS / NN0436006 / 7000 |
How Dilcon Community Boarding School BIA Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Dilcon Community Boarding School BIA | Navajo Nation avg | Federal benchmark |
|---|---|---|---|
| Total violations | 114 | 173.7 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 30 | 8 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | None | 100% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 473 | 984 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 170 regulated public water systems in Navajo Nation.
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 Dilcon Community Boarding School BIA water safe to drink? ▼
How many people does Dilcon Community Boarding School BIA serve? ▼
What type of violations does Dilcon Community Boarding School BIA have? ▼
Has PFAS been detected in Dilcon Community Boarding School BIA water? ▼
What water source does Dilcon Community Boarding School BIA 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.