States › New Hampshire › Coos County

Coos County, NH Water Quality

Water quality data for 14 public water systems serving Coos County, New Hampshire — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 14 water systems · 17 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

Coos County Earns a B

Coos County: 17 communities across 14 water systems. 100.0% have no open violations.

  • Median lead where detected: 30.00 ppb
  • 6 communities with a lead detection, 1 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 2 with significant inspection deficiencies
  • 100.0% of communities have no open violations
30 ppb
Median Lead Level
County-wide, 90th percentile
14
Water Systems
Active CWS & NTNCWS
100%
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
  • Clarksville
    Not reported
    No federal limits exceeded on record
    B
  • Gorham
    Not reported
    No federal limits exceeded on record
    B
  • Milan
    Not reported
    No federal limits exceeded on record
    B
  • Pittsburg
    Not reported
    No federal limits exceeded on record
    B
  • Berlin
    Not detected
    Copper above the 1,300 ppb action level
    A
⚠ Needs Attention
  • Carroll
    29.00 ppb
    Lead above the 15 ppb action level
    C
  • Stratford
    48.00 ppb
    Lead above the 15 ppb action level
    C
  • Randolph
    30.00 ppb
    Lead above the 15 ppb action level
    C
  • Stewartstown
    28.00 ppb
    Lead above the 15 ppb action level
    C
  • Colebrook
    31.00 ppb
    Lead above the 15 ppb action level
    C
County Lead Level — Median 30 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 30 ppb — 200% of the federal action level
Systems by Lead Level
10 – 15 ppb
6
No Data
11

All Cities in Coos County

Berlin Not detected A
Lancaster Not reported B
Gorham Not reported B
Whitefield Not reported B
Northumberland 30.00 ppb C
Whitefield Not reported B
Colebrook 31.00 ppb C
Carroll 29.00 ppb C
Stratford 48.00 ppb C
Errol Not reported B
Milan Not reported B
Pittsburg Not reported B
Randolph 30.00 ppb C
Stewartstown 28.00 ppb C
Columbia Not reported B
Clarksville Not reported B
Jefferson Not reported B
Showing 17 cities
No active violations Active violations

About Coos County Drinking Water

Coos County is served by 14 water systems covering 17 communities. No community here has an open violation on record.

Of the communities reporting lead results, 6 recorded a detection, with a median of 30.00 ppb — 200% of the federal action level. 1 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 2 of them.

Frequently Asked Questions

Is Coos County tap water safe to drink?▼
No community in Coos County has an open violation on record. No community has PFAS above the federal limit on record.
What is the lead level in Coos County?▼
Among communities with a detection the median is 30.00 ppb, 200% of the 15 ppb action level. 1 reported none detected and 10 reported no result.
How many water systems serve Coos County?▼
14 community water systems serve 17 communities here.
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