States ›Montana ›Blaine County ›Fort Belknap Agency

Fort Belknap Agency, MT Tap Water Quality 2026

Water quality report for Fort Belknap Agency, MT — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at Fort Belknap Agency's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Fort Belknap Agency Water System PWSID: 083090041 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 1.00 ppb, 7% of the action level and no violations are open. PFAS has never been sampled at this system.

C

Fort Belknap Agency earns a C for water quality

Graded on violations and lead, with state inspection findings. PFAS not tested.

Lead: 1.00 ppb — 7% of the federal action level
PFAS never sampled at this system
83 violations since 2015, 71 health-based
No violations currently open
Fort Belknap Agency's lead level vs. all Montana community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 1.00 ppb — 7% of the federal action level
✓ Lower lead than 99% of Montana utilities
Population Served
1481
~461 connections
Water Source
Surface water
Drawn from surface water — SDWIS source code SW
Active Violations
0
83 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
7% of EPA action level
1.00 ppb
Action level: 15 ppb
Copper (Cu)
90th percentile of tap samples. SDWIS reports a copper figure only when a system exceeds the action level, so any value here is an exceedance.
167.7% of EPA action level
2,180 ppb
Action level: 1,300 ppb
The 90th-percentile lead result is 1.00 ppb, 7% of the 15 ppb federal action level. The action level is a treatment trigger, not a legal maximum, and it is measured across sampled taps rather than at any single home. Copper reached the action level here; a copper figure appears in SDWIS only when a system triggers it.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
TTHM MCL EXCEEDANCE 0.106 MG/L 0.080 mg/L 2026 Archived
TTHM MCL EXCEEDANCE 0.102 MG/L 0.080 mg/L 2025 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.68 RATIO TT 2025 Archived
TTHM MCL EXCEEDANCE 0.104 MG/L 0.080 mg/L 2025 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.68 RATIO TT 2025 Archived
TTHM MCL EXCEEDANCE 0.101 MG/L 0.080 mg/L 2025 Archived
TTHM MCL EXCEEDANCE 0.109 MG/L 0.080 mg/L 2025 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.71 RATIO TT 2025 Archived
DICHLOROMETHANE MONITORING AND REPORTING — 0.005 mg/L 2025 Resolved
TTHM MCL EXCEEDANCE 0.115 MG/L 0.080 mg/L 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.72 RATIO TT 2024 Archived
TTHM MCL EXCEEDANCE 0.114 MG/L 0.080 mg/L 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.81 RATIO TT 2024 Archived
TTHM MCL EXCEEDANCE 0.107 MG/L 0.080 mg/L 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.89 RATIO TT 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.89 RATIO TT 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.88 RATIO TT 2024 Archived
TTHM MCL EXCEEDANCE 0.095 MG/L 0.080 mg/L 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.89 RATIO TT 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.91 RATIO TT 2024 Archived
CARBON, TOTAL TREATMENT TECHNIQUE 0.98 RATIO TT 2024 Archived
TTHM MCL EXCEEDANCE 0.085 MG/L 0.080 mg/L 2023 Archived
TTHM MCL EXCEEDANCE 0.092 MG/L 0.080 mg/L 2022 Resolved
TTHM MCL EXCEEDANCE 0.103 MG/L 0.080 mg/L 2022 Resolved
TTHM MCL EXCEEDANCE 0.125 MG/L 0.080 mg/L 2021 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE 0.94 RATIO TT 2021 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE 0.99 RATIO TT 2021 Resolved
TTHM MCL EXCEEDANCE 0.13 MG/L 0.080 mg/L 2021 Resolved
TTHM MCL EXCEEDANCE 0.138 MG/L 0.080 mg/L 2021 Resolved
TTHM MCL EXCEEDANCE 0.127 MG/L 0.080 mg/L 2021 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2021 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2021 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2021 Resolved
TTHM MCL EXCEEDANCE 0.119 MG/L 0.080 mg/L 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
TTHM MCL EXCEEDANCE 0.114 MG/L 0.080 mg/L 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
Surface Water Treatment Rule MONITORING AND REPORTING — — 2020 Resolved
TTHM MCL EXCEEDANCE 0.082 MG/L 0.080 mg/L 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
Surface Water Treatment Rule MONITORING AND REPORTING — — 2020 Resolved
TTHM MCL EXCEEDANCE 0.088 MG/L 0.080 mg/L 2020 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2020 Resolved
Asbestos MONITORING AND REPORTING — 7 MFL 2020–2022 Resolved
TTHM MCL EXCEEDANCE 0.1 MG/L 0.080 mg/L 2019 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2019 Resolved
TTHM MONITORING AND REPORTING — 0.080 mg/L 2019 Resolved
Total Haloacetic Acids (HAA5) MONITORING AND REPORTING — 0.060 mg/L 2019 Resolved
TTHM MCL EXCEEDANCE 0.102 MG/L 0.080 mg/L 2019 Resolved
CARBON, TOTAL MONITORING AND REPORTING — TT 2019 Archived
CARBON, TOTAL MONITORING AND REPORTING — TT 2019 Archived
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2019 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2019 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2019 Resolved
TTHM MCL EXCEEDANCE 0.122 MG/L 0.080 mg/L 2019 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2019 Resolved
TTHM MCL EXCEEDANCE 0.114 MG/L 0.080 mg/L 2018 Resolved
TTHM MCL EXCEEDANCE 0.119 MG/L 0.080 mg/L 2018 Resolved
CARBON, TOTAL MONITORING AND REPORTING — TT 2018 Archived
CARBON, TOTAL MONITORING AND REPORTING — TT 2018 Archived
TTHM MCL EXCEEDANCE 0.119 MG/L 0.080 mg/L 2018 Resolved
TTHM MCL EXCEEDANCE 0.134 MG/L 0.080 mg/L 2018 Resolved
CARBON, TOTAL MONITORING AND REPORTING — TT 2018 Resolved
TTHM MCL EXCEEDANCE 0.133 MG/L 0.080 mg/L 2017 Resolved
TTHM MCL EXCEEDANCE 0.13 MG/L 0.080 mg/L 2017 Resolved
TTHM MCL EXCEEDANCE 0.124 MG/L 0.080 mg/L 2017 Resolved
TTHM MCL EXCEEDANCE 0.117 MG/L 0.080 mg/L 2017 Resolved
TTHM MCL EXCEEDANCE 0.113 MG/L 0.080 mg/L 2016 Resolved
TTHM MCL EXCEEDANCE 0.111 MG/L 0.080 mg/L 2016 Resolved
Surface Water Treatment Rule MONITORING AND REPORTING — — 2016 Resolved
TTHM MCL EXCEEDANCE 0.108 MG/L 0.080 mg/L 2016 Resolved
TTHM MCL EXCEEDANCE 0.127 MG/L 0.080 mg/L 2016 Resolved
TTHM MCL EXCEEDANCE 0.129 MG/L 0.080 mg/L 2015 Resolved
TTHM MCL EXCEEDANCE 0.143 MG/L 0.080 mg/L 2015 Resolved
TTHM MCL EXCEEDANCE 0.167 MG/L 0.080 mg/L 2015 Resolved
TTHM MCL EXCEEDANCE 0.157 MG/L 0.080 mg/L 2015 Resolved
CARBON, TOTAL TREATMENT TECHNIQUE — TT 2015 Resolved
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

83 violations are on record since 2015, of which 71 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Fort Belknap Agency Water System
PWSID 083090041
Water source Surface water — Drawn from surface water — SDWIS source code SW
Population served 1,481
Service connections 461
Systems serving this area 1
Regulator US EPA (tribal primacy)
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Fort Belknap Agency tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 1.00 ppb, 7% of the action level.
Does Fort Belknap Agency water have PFAS? ▼
This system has never been sampled for PFAS. EPA's national monitoring covered systems serving 3,300 people or more, so no results exist — which is not evidence that none is present.
Who supplies water to Fort Belknap Agency? ▼
Fort Belknap Agency Water System (PWSID 083090041). Surface water. Drawn from surface water — SDWIS source code SW
When was this system last inspected? ▼
It was last inspected on 2025-08-20. Inspectors recorded 2 significant deficiencies.

What Should Fort Belknap Agency Residents Do?

1
Read your annual water report
Your supplier publishes a Consumer Confidence Report each July covering the prior year.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Flush before drinking
If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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