State distribution
Hardness across indexed ZIPs
Counts describe published ZIP profiles, not a population-weighted statewide sample.
Soft · 0–60 PPM4
Moderately hard · 61–120 PPM20
Hard · 121–180 PPM8
Very hard · 181+ PPM1
State water index
Maryland water hardness
Search 15 indexed communities and 42 ZIP profiles, then compare the underlying utility, source, distance, and reporting context.
Median regional evidence
102PPM
Moderately Hard
Indexed range 27.7–211 PPM
- ZIP profiles
- 42
- Cities
- 15
- Matched utilities
- 17
- Counties
- 11
Understanding Maryland
Why local comparisons matter here
Maryland crosses Appalachian terrain, the Piedmont, and the Chesapeake Coastal Plain, while the Washington suburbs include large regional surface-water systems.
In this index, moderately hard is the largest category, covering 20 of 33 profiles with hardness data. The state median is 102 PPM, but the full indexed range is 27.7–211 PPM.
Evidence coverage
What the current records support
- Hardness estimate
- 79%
- Lead 90th percentile
- 100%
- Copper 90th percentile
- 2%
14
Low-confidence hardness profiles
17
Research-comparison eligible profiles
Reported source water
Utility source mix
- Groundwater
- 9
- Surface water
- 8
Highest medians
Highest eligible city medians
Lowest medians
Lowest eligible city medians
City directory
Explore Maryland by city
Search by city or county, then sort by name, hardness, or ZIP coverage.
15 cities · 42 ZIP profiles
15 cities found
Aberdeen
Harford County · 1 ZIP
64PPM regional
Single regional valueNo active flag
Baltimore
Baltimore City County · 23 ZIPs
102PPM regional
Regional range 102–211No active flag
Bowie
Prince George'S County · 2 ZIPs
94PPM regional
Single regional valueNo active flag
Brunswick
Frederick County · 1 ZIP
137PPM regional
Single regional valueNo active flag
Cambridge
Dorchester County · 1 ZIP
32PPM regional
Single regional valueNo active flag
Cumberland
Allegany County · 1 ZIP
130PPM regional
Single regional valueNo active flag
Frederick
Frederick County · 3 ZIPs
137PPM regional
Regional range 125–137No active flag
Fruitland
Wicomico County · 1 ZIP
28PPM regional
Single regional valueNo active flag
Hagerstown
Washington County · 1 ZIP
81PPM regional
Single regional valueNo active flag
Havre De Grace
Harford County · 1 ZIP
83PPM regional
Single regional valueNo active flag
Prince Frederick
Calvert County · 1 ZIP
127PPM regional
Single regional valueNo active flag
Salisbury
Wicomico County · 2 ZIPs
39PPM regional
Regional range 31.1–47.7No active flag
Stevensville
Queen Anne'S County · 1 ZIP
75PPM regional
Single regional valueNo active flag
Taneytown
Carroll County · 1 ZIP
77PPM regional
Single regional valueNo active flag
Westminster
Carroll County · 2 ZIPs
139PPM regional
Regional range 132–145No active flag
County comparison
Highest regional-evidence county medians
| County | Median | Range | ZIP profiles |
|---|---|---|---|
| Frederick County | 137 PPM | 125–137 | 4 |
| Carroll County | 132 PPM | 76.6–145 | 3 |
| Allegany County | 130 PPM | 130–130 | 1 |
| Calvert County | 127 PPM | 127–127 | 1 |
| Baltimore City County | 102 PPM | 102–211 | 23 |
| Prince George'S County | 94 PPM | 93.6–93.6 | 2 |
| Washington County | 81 PPM | 81–81 | 1 |
| Queen Anne'S County | 75 PPM | 75.4–75.4 | 1 |
| Harford County | 74 PPM | 64.4–82.8 | 2 |
| Dorchester County | 32 PPM | 31.6–31.6 | 1 |
| Wicomico County | 31 PPM | 27.7–47.7 | 3 |