State distribution
Hardness across indexed ZIPs
Counts describe published ZIP profiles, not a population-weighted statewide sample.
Soft · 0–60 PPM31
Moderately hard · 61–120 PPM2
Hard · 121–180 PPM0
Very hard · 181+ PPM0
State water index
Rhode Island water hardness
Search 12 indexed communities and 33 ZIP profiles, then compare the underlying utility, source, distance, and reporting context.
Median regional evidence
20PPM
Soft
Indexed range 14.6–65.5 PPM
- ZIP profiles
- 33
- Cities
- 12
- Matched utilities
- 30
- Counties
- 4
Understanding Rhode Island
Why local comparisons matter here
Rhode Island's compact water landscape includes major reservoir supply, smaller surface systems, and local groundwater in coastal and inland communities.
In this index, soft is the largest category, covering 31 of 33 profiles with hardness data. The state median is 20 PPM, but the full indexed range is 14.6–65.5 PPM.
Evidence coverage
What the current records support
- Hardness estimate
- 100%
- Lead 90th percentile
- 100%
- Copper 90th percentile
- 9%
1
Low-confidence hardness profiles
29
Research-comparison eligible profiles
Reported source water
Utility source mix
- Groundwater
- 17
- Surface water
- 13
Highest medians
Highest eligible city medians
- 1. Providence20 PPM
- 2. East Providence20 PPM
- 3. Cranston19 PPM
Lowest medians
Lowest eligible city medians
- 1. Cranston19 PPM
- 2. East Providence20 PPM
- 3. Providence20 PPM
City directory
Explore Rhode Island by city
Search by city or county, then sort by name, hardness, or ZIP coverage.
12 cities · 33 ZIP profiles
12 cities found
Central Falls
Providence County · 1 ZIP
22PPM regional
Single regional valueNo active flag
Charlestown
Washington County · 1 ZIP
54PPM regional
Single regional value1 active record
Cranston
Providence County · 5 ZIPs
19PPM regional
Regional range 17.9–20No active flag
East Providence
Providence County · 3 ZIPs
20PPM regional
Regional range 18.9–21.9No active flag
Hopkinton
Washington County · 1 ZIP
62PPM regional
Single regional value2 active records
Newport
Newport County · 2 ZIPs
23PPM regional
Regional range 16.9–29No active flag
Pawtucket
Providence County · 2 ZIPs
22PPM regional
Single regional valueNo active flag
Providence
Providence County · 11 ZIPs
20PPM regional
Regional range 18.9–21.1No active flag
Tiverton
Newport County · 1 ZIP
46PPM regional
Single regional valueNo active flag
Warwick
Kent County · 4 ZIPs
18PPM regional
Regional range 14.6–17.9No active flag
Westerly
Washington County · 1 ZIP
66PPM regional
Single regional valueNo active flag
Woonsocket
Providence County · 1 ZIP
33PPM regional
Single regional valueNo active flag
County comparison
Highest regional-evidence county medians
| County | Median | Range | ZIP profiles |
|---|---|---|---|
| Washington County | 62 PPM | 53.9–65.5 | 3 |
| Newport County | 29 PPM | 16.9–46.2 | 3 |
| Providence County | 20 PPM | 17.9–33.3 | 23 |
| Kent County | 18 PPM | 14.6–17.9 | 4 |