F0/100
ROCKY BOY AGENCY WATER SYSTEM — Water Quality Report 2026
Serving 1,442 people · Montana
Water Source
Groundwater
County
—
System ID
083090079
Violations
89
Contaminant Test Results
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 1.75 mg/L | 1.30 mg/L | Over Limit |
Lead (90th percentile) | 0.001 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
3
Violations (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: January 1, 2023 – March 31, 2023Enforcement: Resolving — corrective action underway
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: October 1, 2022 – December 31, 2022Enforcement: Resolving — corrective action underway
TIER 3Resolved
Exceeded the MCL for disinfection byproducts
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: July 1, 2022 – September 30, 2022Enforcement: Resolving — corrective action underway
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About ROCKY BOY AGENCY WATER SYSTEM
Is ROCKY BOY AGENCY WATER SYSTEM water safe to drink?
ROCKY BOY AGENCY WATER SYSTEM water receives a grade of F (0/100), which is considered failing. 1 contaminant(s) exceed EPA legal limits and 89 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has ROCKY BOY AGENCY WATER SYSTEM detected?
2 contaminants were tested in ROCKY BOY AGENCY WATER SYSTEM's water. Notable contaminants include Copper (90th percentile), Lead (90th percentile). 1 exceed EPA legal limits (MCLs). 2 exceed EPA health goals (MCLGs).
Does ROCKY BOY AGENCY WATER SYSTEM have any EPA violations?
Yes, ROCKY BOY AGENCY WATER SYSTEM has 89 EPA violation(s) on record, with the most recent in 2023. Violation types include MR, TT, Other. 5 are health-based violations.
How many people does ROCKY BOY AGENCY WATER SYSTEM serve?
ROCKY BOY AGENCY WATER SYSTEM serves approximately 1,442 people, Montana.
What type of water does ROCKY BOY AGENCY WATER SYSTEM provide?
ROCKY BOY AGENCY WATER SYSTEM sources its water from groundwater. Groundwater is pumped from underground aquifers, which often provides natural filtration. The utility's system ID is 083090079.
How does ROCKY BOY AGENCY WATER SYSTEM compare to other utilities in Montana?
ROCKY BOY AGENCY WATER SYSTEM scores 0/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Montana state page for a full comparison of water systems.