State distribution
Hardness across indexed ZIPs
Counts describe published ZIP profiles, not a population-weighted statewide sample.
Soft · 0–60 PPM56
Moderately hard · 61–120 PPM42
Hard · 121–180 PPM0
Very hard · 181+ PPM0
State water index
Connecticut water hardness
Search 52 indexed communities and 98 ZIP profiles, then compare the underlying utility, source, distance, and reporting context.
Median indexed hardness
53PPM
Soft
Indexed range 42.8–114 PPM
- ZIP profiles
- 98
- Cities
- 52
- Matched utilities
- 119
- Counties
- 8
Understanding Connecticut
Why local comparisons matter here
Connecticut combines regional reservoir systems with smaller surface-water supplies and local bedrock or stratified-drift wells across a compact area.
In this index, soft is the largest category, covering 56 of 98 profiles with hardness data. The state median is 53 PPM, but the full indexed range is 42.8–114 PPM.
Evidence coverage
What the current records support
- Hardness estimate
- 100%
- Lead 90th percentile
- 100%
- Copper 90th percentile
- 16%
0
Low-confidence hardness profiles
0
Nearest site more than 25 miles away
Reported source water
Utility source mix
- Groundwater
- 67
- Surface water
- 51
- Groundwater influenced by surface water
- 1
Highest medians
Hardest indexed cities
- 1. Canaan114 PPM
- 2. Bridgewater101 PPM
- 3. Weston96 PPM
- 4. Cornwall94 PPM
- 5. Norwalk92 PPM
Lowest medians
Softest indexed cities
- 1. Winsted43 PPM
- 2. Waterford43 PPM
- 3. Stonington43 PPM
- 4. New London43 PPM
- 5. Putnam44 PPM
City directory
Explore Connecticut by city
Search by city or county, then sort by name, hardness, or ZIP coverage.
52 cities · 98 ZIP profiles
52 cities found
Page 1 of 3
Ansonia
New Haven County · 1 ZIP
73PPM
Single indexed valueNo active flag
Bethel
Fairfield County · 1 ZIP
79PPM
Single indexed valueNo active flag
Bridgeport
Fairfield County · 6 ZIPs
86PPM
Range 81.4–89.6No active flag
Bridgewater
Litchfield County · 1 ZIP
101PPM
Single indexed valueNo active flag
Bristol
Hartford County · 2 ZIPs
47PPM
Range 45.4–47.6No active flag
Canaan
Litchfield County · 1 ZIP
114PPM
Single indexed valueNo active flag
Clinton
Middlesex County · 1 ZIP
45PPM
Single indexed valueNo active flag
Colchester
New London County · 1 ZIP
71PPM
Single indexed value2 active records
Cornwall
Litchfield County · 1 ZIP
94PPM
Single indexed value1 active record
Danbury
Fairfield County · 2 ZIPs
83PPM
Range 83–83.6No active flag
Derby
New Haven County · 1 ZIP
77PPM
Single indexed valueNo active flag
Durham
Middlesex County · 1 ZIP
48PPM
Single indexed valueNo active flag
East Hartford
Hartford County · 2 ZIPs
45PPM
Single indexed valueNo active flag
East Haven
New Haven County · 1 ZIP
57PPM
Single indexed valueNo active flag
Greenwich
Fairfield County · 1 ZIP
89PPM
Single indexed valueNo active flag
Hartford
Hartford County · 7 ZIPs
45PPM
Range 44.7–45.2No active flag
Litchfield
Litchfield County · 1 ZIP
53PPM
Single indexed valueNo active flag
Manchester
Hartford County · 2 ZIPs
45PPM
Range 44.7–46.1No active flag
Meriden
New Haven County · 2 ZIPs
49PPM
Range 47.6–50.1No active flag
Middletown
Middlesex County · 2 ZIPs
46PPM
Single indexed value1 active record
Naugatuck
New Haven County · 2 ZIPs
60PPM
Range 56.4–63.4No active flag
New Britain
Hartford County · 3 ZIPs
46PPM
Range 44.9–45.9No active flag
New Canaan
Fairfield County · 1 ZIP
90PPM
Single indexed valueNo active flag
New Haven
New Haven County · 6 ZIPs
58PPM
Range 52.7–64.3No active flag
County comparison
Highest indexed county medians
| County | Median | Range | ZIP profiles |
|---|---|---|---|
| Fairfield County | 89 PPM | 77.1–96.3 | 27 |
| Tolland County | 86 PPM | 86.3–86.3 | 1 |
| Litchfield County | 74 PPM | 43–114 | 11 |
| New Haven County | 56 PPM | 47.6–77.9 | 22 |
| Middlesex County | 46 PPM | 45.1–47.9 | 5 |
| Hartford County | 45 PPM | 43.9–47.6 | 24 |
| New London County | 45 PPM | 42.8–70.5 | 7 |
| Windham County | 44 PPM | 44.1–44.1 | 1 |