States › Montana › Yellowstone County

Yellowstone County, MT Water Quality

Water quality data for 9 public water systems serving Yellowstone County, Montana — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 9 water systems · 10 cities
✅
Generally Safe — Most Systems Performing Well

The majority of water systems have no active violations and lead levels well below the federal action level.

B

Yellowstone County Earns a B

Yellowstone County: 10 communities across 9 water systems. 80.0% have no open violations.

  • Median lead where detected: 3.00 ppb
  • 7 communities with a lead detection, 3 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 1 with significant inspection deficiencies
  • 80.0% of communities have no open violations
3 ppb
Median Lead Level
County-wide, 90th percentile
9
Water Systems
Active CWS & NTNCWS
80%
Violation-Free
No active violations on record
How we grade counties: MyWaterIQ uses EPA SDWIS enforcement data — actual MCL violations and lead test results — not the aspirational MCLG targets used by some sites. A grade reflects real compliance history, not theoretical risk. Learn more →

Cities by Water Quality

⭐ Best Performing
  • Lockwood
    3.00 ppb
    No federal limits exceeded on record
    A
  • Custer
    Not detected
    No federal limits exceeded on record
    B
  • Shepherd
    Not detected
    No federal limits exceeded on record
    B
  • Billings
    5.00 ppb
    Lead at 5.00 ppb, above a third of the action level
    A
  • Broadview
    11.00 ppb
    Lead at 11.00 ppb, above a third of the action level
    B
⚠ Needs Attention
  • Worden
    3.00 ppb
    Copper above the 1,300 ppb action level
    D
  • Ballantine
    3.00 ppb
    Copper above the 1,300 ppb action level
    D
  • Laurel
    2.00 ppb
    Copper above the 1,300 ppb action level
    B
  • Huntley
    2.00 ppb
    Copper above the 1,300 ppb action level
    B
  • Mountain View Colony
    Not detected
    2 significant inspection deficiencies
    B
County Lead Level — Median 3 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 3 ppb — 20% of the federal action level
Systems by Lead Level
Under 5 ppb
5
5 – 10 ppb
1
10 – 15 ppb
1
No Data
3

All Cities in Yellowstone County

Billings 5.00 ppb A
Laurel 2.00 ppb B
Lockwood 3.00 ppb A
Worden 3.00 ppb D
Huntley 2.00 ppb B
Ballantine 3.00 ppb D
Broadview 11.00 ppb B
Mountain View Colony Not detected B
Custer Not detected B
Shepherd Not detected B
Showing 10 cities
No active violations Active violations

About Yellowstone County Drinking Water

Yellowstone County is served by 9 water systems covering 10 communities. 80% have no open violations.

Of the communities reporting lead results, 7 recorded a detection, with a median of 3.00 ppb — 20% of the federal action level. 3 reported none detected, which means below the laboratory limit rather than an absence of lead.

No community here has PFAS above the federal limit on record. State inspectors recorded significant deficiencies at 1 of them.

Frequently Asked Questions

Is Yellowstone County tap water safe to drink?▼
80% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in Yellowstone County?▼
Among communities with a detection the median is 3.00 ppb, 20% of the 15 ppb action level. 3 reported none detected and 0 reported no result.
How many water systems serve Yellowstone County?▼
9 community water systems serve 10 communities here.
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