State distribution
Hardness across indexed ZIPs
Counts describe published ZIP profiles, not a population-weighted statewide sample.
Soft · 0–60 PPM5
Moderately hard · 61–120 PPM35
Hard · 121–180 PPM2
Very hard · 181+ PPM0
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 indexed hardness
90PPM
Moderately Hard
Indexed range 57.8–167 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 35 of 42 profiles with hardness data. The state median is 90 PPM, but the full indexed range is 57.8–167 PPM.
Evidence coverage
What the current records support
- Hardness estimate
- 100%
- Lead 90th percentile
- 100%
- Copper 90th percentile
- 2%
9
Low-confidence hardness profiles
9
Nearest site more than 25 miles away
Reported source water
Utility source mix
- Groundwater
- 9
- Surface water
- 8
Highest medians
Hardest indexed cities
- 1. Cumberland167 PPM
- 2. Taneytown121 PPM
- 3. Havre De Grace94 PPM
- 4. Westminster93 PPM
- 5. Baltimore90 PPM
Lowest medians
Softest indexed cities
- 1. Prince Frederick58 PPM
- 2. Salisbury59 PPM
- 3. Fruitland59 PPM
- 4. Cambridge59 PPM
- 5. Stevensville62 PPM
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
88PPM
Single indexed valueNo active flag
Baltimore
Baltimore City County · 23 ZIPs
90PPM
Range 88.1–94.6No active flag
Bowie
Prince George'S County · 2 ZIPs
68PPM
Range 67.1–68.8No active flag
Brunswick
Frederick County · 1 ZIP
85PPM
Single indexed valueNo active flag
Cambridge
Dorchester County · 1 ZIP
59PPM
Single indexed valueNo active flag
Cumberland
Allegany County · 1 ZIP
167PPM
Single indexed valueNo active flag
Frederick
Frederick County · 3 ZIPs
83PPM
Range 81–83.6No active flag
Fruitland
Wicomico County · 1 ZIP
59PPM
Single indexed valueNo active flag
Hagerstown
Washington County · 1 ZIP
81PPM
Single indexed valueNo active flag
Havre De Grace
Harford County · 1 ZIP
94PPM
Single indexed valueNo active flag
Prince Frederick
Calvert County · 1 ZIP
58PPM
Single indexed valueNo active flag
Salisbury
Wicomico County · 2 ZIPs
59PPM
Range 58.8–58.9No active flag
Stevensville
Queen Anne'S County · 1 ZIP
62PPM
Single indexed valueNo active flag
Taneytown
Carroll County · 1 ZIP
121PPM
Single indexed valueNo active flag
Westminster
Carroll County · 2 ZIPs
93PPM
Range 92.2–94.6No active flag
County comparison
Highest indexed county medians
| County | Median | Range | ZIP profiles |
|---|---|---|---|
| Allegany County | 167 PPM | 167–167 | 1 |
| Carroll County | 95 PPM | 92.2–121 | 3 |
| Harford County | 91 PPM | 87.8–93.6 | 2 |
| Baltimore City County | 90 PPM | 88.1–94.6 | 23 |
| Frederick County | 83 PPM | 81–85 | 4 |
| Washington County | 81 PPM | 80.9–80.9 | 1 |
| Prince George'S County | 68 PPM | 67.1–68.8 | 2 |
| Queen Anne'S County | 62 PPM | 62.2–62.2 | 1 |
| Dorchester County | 59 PPM | 58.7–58.7 | 1 |
| Wicomico County | 59 PPM | 58.8–58.9 | 3 |
| Calvert County | 58 PPM | 57.8–57.8 | 1 |