State distribution
Hardness across indexed ZIPs
Counts describe published ZIP profiles, not a population-weighted statewide sample.
Soft · 0–60 PPM28
Moderately hard · 61–120 PPM60
Hard · 121–180 PPM6
Very hard · 181+ PPM4
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 regional evidence
89PPM
Moderately Hard
Indexed range 15.8–254 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, moderately hard is the largest category, covering 60 of 98 profiles with hardness data. The state median is 89 PPM, but the full indexed range is 15.8–254 PPM.
Evidence coverage
What the current records support
- Hardness estimate
- 100%
- Lead 90th percentile
- 100%
- Copper 90th percentile
- 16%
5
Low-confidence hardness profiles
84
Research-comparison eligible profiles
Reported source water
Utility source mix
- Groundwater
- 67
- Surface water
- 51
- Groundwater influenced by surface water
- 1
Highest medians
Highest eligible city medians
- 1. New Britain64 PPM
- 2. Hartford52 PPM
Lowest medians
Lowest eligible city medians
- 1. Hartford52 PPM
- 2. New Britain64 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
90PPM regional
Single regional valueNo active flag
Bethel
Fairfield County · 1 ZIP
95PPM regional
Single regional valueNo active flag
Bridgeport
Fairfield County · 6 ZIPs
89PPM regional
Regional range 85.9–95.1No active flag
Bridgewater
Litchfield County · 1 ZIP
254PPM regional
Single regional valueNo active flag
Bristol
Hartford County · 2 ZIPs
69PPM regional
Single regional valueNo active flag
Canaan
Litchfield County · 1 ZIP
205PPM regional
Single regional valueNo active flag
Clinton
Middlesex County · 1 ZIP
64PPM regional
Single regional valueNo active flag
Colchester
New London County · 1 ZIP
71PPM regional
Single regional value2 active records
Cornwall
Litchfield County · 1 ZIP
205PPM regional
Single regional value3 active records
Danbury
Fairfield County · 2 ZIPs
95PPM regional
Single regional valueNo active flag
Derby
New Haven County · 1 ZIP
89PPM regional
Single regional valueNo active flag
Durham
Middlesex County · 1 ZIP
74PPM regional
Single regional value4 active records
East Hartford
Hartford County · 2 ZIPs
50PPM regional
Regional range 47.4–52No active flag
East Haven
New Haven County · 1 ZIP
99PPM regional
Single regional valueNo active flag
Greenwich
Fairfield County · 1 ZIP
119PPM regional
Single regional valueNo active flag
Hartford
Hartford County · 7 ZIPs
52PPM regional
Regional range 49–52No active flag
Litchfield
Litchfield County · 1 ZIP
92PPM regional
Single regional valueNo active flag
Manchester
Hartford County · 2 ZIPs
43PPM regional
Single regional valueNo active flag
Meriden
New Haven County · 2 ZIPs
79PPM regional
Regional range 74.2–83.1No active flag
Middletown
Middlesex County · 2 ZIPs
64PPM regional
Single regional value1 active record
Naugatuck
New Haven County · 2 ZIPs
90PPM regional
Single regional valueNo active flag
New Britain
Hartford County · 3 ZIPs
64PPM regional
Regional range 64.3–69.3No active flag
New Canaan
Fairfield County · 1 ZIP
114PPM regional
Single regional valueNo active flag
New Haven
New Haven County · 6 ZIPs
89PPM regional
Regional range 85.9–90.4No active flag
County comparison
Highest regional-evidence county medians
| County | Median | Range | ZIP profiles |
|---|---|---|---|
| Litchfield County | 138 PPM | 52.3–254 | 11 |
| Fairfield County | 102 PPM | 85.9–123 | 27 |
| Tolland County | 98 PPM | 98.1–98.1 | 1 |
| New Haven County | 90 PPM | 74.2–98.9 | 22 |
| Middlesex County | 64 PPM | 58.3–74.2 | 5 |
| Hartford County | 52 PPM | 40.5–69.3 | 24 |
| New London County | 23 PPM | 15.8–71.2 | 7 |
| Windham County | 19 PPM | 18.9–18.9 | 1 |