States › Connecticut › New London County

New London County, CT Water Quality

Water quality data for 16 public water systems serving New London County, Connecticut — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 16 water systems · 21 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

New London County Earns a B

New London County: 21 communities across 16 water systems. 95.2% have no open violations.

  • Median lead where detected: 1.70 ppb
  • 6 communities with a lead detection, 15 reporting none detected
  • 6 communities with PFAS above the federal limit
  • 2 with significant inspection deficiencies
  • 95.2% of communities have no open violations
1.7 ppb
Median Lead Level
County-wide, 90th percentile
16
Water Systems
Active CWS & NTNCWS
95%
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
  • Groton
    Not detected
    No federal limits exceeded on record
    A
  • New London
    Not detected
    No federal limits exceeded on record
    A
  • Waterford
    1.50 ppb
    No federal limits exceeded on record
    A
  • Stonington
    3.00 ppb
    No federal limits exceeded on record
    A
  • Mystic
    3.00 ppb
    No federal limits exceeded on record
    A
⚠ Needs Attention
  • Norwich
    Not detected
    PFAS above the limit at 1 of 3 sampling points
    D
  • Bozrah
    Not detected
    PFAS above the limit at 1 of 3 sampling points
    D
  • Preston
    Not detected
    PFAS above the limit at 1 of 3 sampling points
    D
  • Franklin
    Not detected
    PFAS above the limit at 1 of 3 sampling points
    D
  • East Lyme
    Not detected
    PFAS above the limit at 2 of 6 sampling points
    D
County Lead Level — Median 1.7 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 1.7 ppb — 11.3% of the federal action level
Systems by Lead Level
Under 5 ppb
6
No Data
15

All Cities in New London County

Norwich Not detected D
Groton Not detected A
New London Not detected A
Waterford 1.50 ppb A
East Lyme Not detected D
Stonington 3.00 ppb A
Griswold Not detected A
Montville Not detected B
Colchester Not detected D
Mystic 3.00 ppb A
Ledyard Not detected B
Sprague Not detected B
Old Lyme Not detected B
Bozrah Not detected D
North Stonington 1.90 ppb B
Lebanon Not detected C
Preston Not detected D
Lisbon Not detected A
Salem 0.60 ppb B
Voluntown 0.60 ppb B
Franklin Not detected D
Showing 21 cities
No active violations Active violations

About New London County Drinking Water

New London County is served by 16 water systems covering 21 communities. 95% have no open violations.

Of the communities reporting lead results, 6 recorded a detection, with a median of 1.70 ppb — 11% of the federal action level. 15 reported none detected, which means below the laboratory limit rather than an absence of lead.

6 of 21 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 2 of them.

Frequently Asked Questions

Is New London County tap water safe to drink?▼
95% of communities have no open violation. 6 of 21 have PFAS above the federal limit, which is the main open concern.
What is the lead level in New London County?▼
Among communities with a detection the median is 1.70 ppb, 11% of the 15 ppb action level. 15 reported none detected and 0 reported no result.
How many water systems serve New London County?▼
16 community water systems serve 21 communities here.
← Back to Connecticut water quality overview