Fort Defiance-Window Rock-St Michaels Ntua
PWSID: NN0403000
This system currently has unresolved violations for: 8000. These violations mean contaminant levels exceeded EPA limits or required treatment was not performed.
This system has more violations on record than 83% of water systems in Arizona.
Violation trend: 1.2 per year over the last 5 years, down from 6.6 per year in the previous 5.
System Details
| Population Served | 12,869 |
| Service Connections | 3,763 |
| Water Source | Groundwater |
| System Type | Community Water System |
| Owner | Native American |
| Status | Active |
| City | Ft Defiance |
| EPA ZIP on File | 86504 |
Areas Served
Lead & Copper Testing
| Contaminant | Level | EPA Action Level | Status |
|---|---|---|---|
| Lead (90th percentile) | 0.0020 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0020 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0020 mg/L | 0.015 mg/L | Below Action Level |
| Lead (90th percentile) | 0.0016 mg/L | 0.015 mg/L | Below Action Level |
2 Active Violations
| Contaminant | Violation | Date | Health-Based | Status |
|---|---|---|---|---|
| 8000 | TT | 2025-02-01 | Yes | Open |
| 7500 | Other | 2025-02-01 | Open |
Violation History (67 total)
| Contaminant | Violation | Date | Health-Based | Status |
|---|---|---|---|---|
| 2950 | MCL Measured: 0.0844 MG/L | 2024-10-01 | Yes | Acknowledged |
| 2950 | MCL Measured: 0.0844 MG/L | 2024-10-01 | Yes | Returned to Compliance |
| 1052 | MR | 2022-01-01 | Major | Acknowledged |
| 1052 | MR | 2022-01-01 | Major | Acknowledged |
| 2456 | MR | 2018-07-01 | Major | Returned to Compliance |
| 2456 | MR | 2018-07-01 | Major | Returned to Compliance |
| 2456 | MR | 2018-07-01 | Major | Returned to Compliance |
| 2950 | MR | 2018-07-01 | Major | Returned to Compliance |
| 2950 | MR | 2018-07-01 | Major | Returned to Compliance |
| 2950 | MR | 2018-07-01 | Major | Returned to Compliance |
| 2456 | MR | 2018-04-01 | Major | Returned to Compliance |
| 2456 | MR | 2018-04-01 | Major | Returned to Compliance |
| 2456 | MR | 2018-04-01 | Major | Returned to Compliance |
| 2950 | MR | 2018-04-01 | Major | Returned to Compliance |
| 2950 | MR | 2018-04-01 | Major | Returned to Compliance |
| 2950 | MR | 2018-04-01 | Major | Returned to Compliance |
| 1040 | MR | 2018-01-01 | Major | Returned to Compliance |
| 1040 | MR | 2018-01-01 | Major | Returned to Compliance |
| 1040 | MR | 2018-01-01 | Major | Returned to Compliance |
| 1041 | MR | 2018-01-01 | Major | Returned to Compliance |
| 1041 | MR | 2018-01-01 | Major | Returned to Compliance |
| 1041 | MR | 2018-01-01 | Major | Returned to Compliance |
| 2950 | MCL Measured: 0.0843 MG/L | 2017-01-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0843 MG/L | 2017-01-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0843 MG/L | 2017-01-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0843 MG/L | 2017-01-01 | Yes | Returned to Compliance |
| 7500 | Other | 2017-01-01 | Returned to Compliance | |
| 7500 | Other | 2017-01-01 | Returned to Compliance | |
| 7500 | Other | 2017-01-01 | Returned to Compliance | |
| 2950 | MCL Measured: 0.0829 MG/L | 2016-10-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0829 MG/L | 2016-10-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0829 MG/L | 2016-10-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0829 MG/L | 2016-10-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0932 MG/L | 2016-07-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0932 MG/L | 2016-07-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0932 MG/L | 2016-07-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.0932 MG/L | 2016-07-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-04-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-04-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-04-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-04-01 | Yes | Returned to Compliance |
| 8000 | Other | 2016-04-01 | Returned to Compliance | |
| 3100 | MR | 2016-02-01 | Returned to Compliance | |
| 3100 | MR | 2016-02-01 | Returned to Compliance | |
| 3100 | MR | 2016-02-01 | Returned to Compliance | |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-01-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-01-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-01-01 | Yes | Returned to Compliance |
| 2950 | MCL Measured: 0.1148 MG/L | 2016-01-01 | Yes | Returned to Compliance |
| 2456 | MR | 2016-01-01 | Major | Returned to Compliance |
Showing 50 of 65 historical violations.
Understanding This Water System's Record
Fort Defiance-Window Rock-St Michaels Ntua is a community water system water system that draws from groundwater sources and serves a population of 12,869 in Ft Defiance, Arizona. This page shows its complete compliance history as reported to the EPA's Safe Drinking Water Information System (SDWIS), the federal database that tracks every public water system in the United States.
What Do These Violations Mean?
Health-based violations mean the system exceeded an EPA maximum contaminant level (MCL) or failed to provide required treatment. These indicate potential health risks from contaminants like lead, arsenic, bacteria, nitrates, or disinfection byproducts. Non-health-based violations involve monitoring, reporting, or procedural requirements — the system missed a testing deadline or failed to notify customers, but contaminant levels were not necessarily unsafe.
What Should You Do?
Your water utility is required to publish an annual Consumer Confidence Report (CCR) that details test results and any violations. If your system has active health-based violations, consider a certified water filter rated for the specific contaminants involved. The contaminant guides on this site explain health risks and filter options for common pollutants. For the most current results, contact your water utility directly — EPA data can lag weeks or months behind real-time testing.