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Windham County, CT Water Quality

Water quality data for 12 public water systems serving Windham County, Connecticut — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 12 water systems · 14 cities
⚠️
Caution Advised — Some Systems Need Attention

Some systems have elevated lead levels or active violations. Check your specific city below.

C

Windham County Earns a C

Windham County: 14 communities across 12 water systems. 71.4% have no open violations.

  • Median lead where detected: 1.80 ppb
  • 8 communities with a lead detection, 6 reporting none detected
  • 4 communities with PFAS above the federal limit
  • 1 with significant inspection deficiencies
  • 71.4% of communities have no open violations
1.8 ppb
Median Lead Level
County-wide, 90th percentile
12
Water Systems
Active CWS & NTNCWS
71%
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
  • Windham
    4.30 ppb
    No federal limits exceeded on record
    A
  • Plainfield
    2.30 ppb
    No federal limits exceeded on record
    B
  • Ashford
    Not detected
    No federal limits exceeded on record
    B
  • Thompson
    1.10 ppb
    Copper above the 1,300 ppb action level
    B
  • Sterling
    Not detected
    Copper above the 1,300 ppb action level
    B
⚠ Needs Attention
  • Killingly
    0.50 ppb
    PFAS above the limit at 2 of 2 sampling points
    D
  • Brooklyn
    0.50 ppb
    PFAS above the limit at 2 of 2 sampling points
    D
  • Chaplin
    14.50 ppb
    1 violation currently open
    D
  • Pomfret
    Not detected
    1 violation currently open
    C
  • Canterbury
    1.30 ppb
    1 violation currently open
    C
County Lead Level — Median 1.8 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 1.8 ppb — 12% of the federal action level
Systems by Lead Level
Under 5 ppb
7
10 – 15 ppb
1
No Data
6

All Cities in Windham County

Windham 4.30 ppb A
Killingly 0.50 ppb D
Putnam Not detected C
Plainfield 2.30 ppb B
Brooklyn 0.50 ppb D
Thompson 1.10 ppb B
Wauregan Not detected B
Sterling Not detected B
Ashford Not detected B
Pomfret Not detected C
Canterbury 1.30 ppb C
Woodstock Not detected C
Chaplin 14.50 ppb D
Eastford 2.30 ppb C
Showing 14 cities
No active violations Active violations

About Windham County Drinking Water

Windham County is served by 12 water systems covering 14 communities. 71% have no open violations.

Of the communities reporting lead results, 8 recorded a detection, with a median of 1.80 ppb — 12% of the federal action level. 6 reported none detected, which means below the laboratory limit rather than an absence of lead.

4 of 14 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 1 of them.

Frequently Asked Questions

Is Windham County tap water safe to drink?▼
71% of communities have no open violation. 4 of 14 have PFAS above the federal limit, which is the main open concern.
What is the lead level in Windham County?▼
Among communities with a detection the median is 1.80 ppb, 12% of the 15 ppb action level. 6 reported none detected and 0 reported no result.
How many water systems serve Windham County?▼
12 community water systems serve 14 communities here.
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