States › New Hampshire › Hillsborough County

Hillsborough County, NH Water Quality

Water quality data for 22 public water systems serving Hillsborough County, New Hampshire — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 22 water systems · 28 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

Hillsborough County Earns a B

Hillsborough County: 28 communities across 22 water systems. 96.4% have no open violations.

  • Median lead where detected: 63.00 ppb
  • 11 communities with a lead detection, 8 reporting none detected
  • 5 communities with PFAS above the federal limit
  • 3 with significant inspection deficiencies
  • 96.4% of communities have no open violations
63 ppb
Median Lead Level
County-wide, 90th percentile
22
Water Systems
Active CWS & NTNCWS
96%
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
  • Nashua
    Not detected
    No federal limits exceeded on record
    A
  • Merrimack
    Not detected
    No federal limits exceeded on record
    A
  • Milford
    2.00 ppb
    No federal limits exceeded on record
    A
  • Amherst
    Not detected
    No federal limits exceeded on record
    A
  • Pelham
    Not reported
    No federal limits exceeded on record
    B
⚠ Needs Attention
  • Windsor
    46.00 ppb
    Lead above the 15 ppb action level
    F
  • Hudson
    Not detected
    PFAS above the limit at 1 of 1 sampling points
    D
  • Mont Vernon
    40.00 ppb
    Lead above the 15 ppb action level
    D
  • Greenfield
    66.00 ppb
    Lead above the 15 ppb action level
    D
  • Wilton
    63.00 ppb
    Lead above the 15 ppb action level
    C
County Lead Level — Median 63 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 63 ppb — 420% of the federal action level
Systems by Lead Level
Under 5 ppb
1
5 – 10 ppb
1
10 – 15 ppb
9
No Data
17

All Cities in Hillsborough County

Manchester Not detected B
Nashua Not detected A
Merrimack Not detected A
Hudson Not detected D
Milford 2.00 ppb A
Litchfield Not detected C
Amherst Not detected A
Bedford Not detected B
Goffstown Not detected B
Peterborough 9.00 ppb A
Pelham Not reported B
Hillsborough 33.00 ppb C
Wilton 63.00 ppb C
Wilton 63.00 ppb C
Antrim Not reported B
Greenville 110.00 ppb C
Bennington Not reported B
Hancock Not reported B
Hollis Not reported B
New Ipswich Not reported B
Weare Not reported B
Mont Vernon 40.00 ppb D
Francestown Not reported B
Deering Not reported B
Windsor 46.00 ppb F
Greenfield 66.00 ppb D
Temple 110.00 ppb C
Mason 110.00 ppb C
Showing 28 cities
No active violations Active violations

About Hillsborough County Drinking Water

Hillsborough County is served by 22 water systems covering 28 communities. 96% have no open violations.

Of the communities reporting lead results, 11 recorded a detection, with a median of 63.00 ppb — 420% of the federal action level. 8 reported none detected, which means below the laboratory limit rather than an absence of lead.

5 of 28 communities have PFAS above the limits EPA set in 2024, measured as a running annual average at each sampling point. State inspectors recorded significant deficiencies at 3 of them.

Frequently Asked Questions

Is Hillsborough County tap water safe to drink?▼
96% of communities have no open violation. 5 of 28 have PFAS above the federal limit, which is the main open concern.
What is the lead level in Hillsborough County?▼
Among communities with a detection the median is 63.00 ppb, 420% of the 15 ppb action level. 8 reported none detected and 9 reported no result.
How many water systems serve Hillsborough County?▼
22 community water systems serve 28 communities here.
← Back to New Hampshire water quality overview