Water Hardness in Maryland
Across 16 measured cities — with 121 more covered by labeled county-level estimates — Maryland's median tap water hardness is 81.0 mg/L (4.7 gpg): moderately hard on the USGS scale. Below: every covered city, the state's hardest and softest water, and the geology that explains it.
Data updated September 13, 2026. Sources: utility-reported water quality data and USGS/EPA Water Quality Portal samples.
What it costs to soften Maryland water
Water softener cost in Maryland at 4.7 gpg prices the equipment and the installation labour against the plumber wages published for Maryland, and labels every range as modelled or measured rather than leaving you to guess which it is.
Maryland · 4.74 grains per gallon
$956–$1,239
installed, midpoint $1,082 — a 24,000-grain unit, the size 4 people at this hardness need.
Salt and drain water over 10 years: $591–$1,211 — the 5,190,300 grains of hardness this household removes, at the national salt price and water rate whose sources are named below. Filter changes and Service contract are omitted rather than assumed.
Sized for 4 people regenerating every 7 days: 9,954 grains of capacity needed, rounded up to the next common residential size. The median of 16 measured Maryland cities in our hardness dataset. Modelled: the standard build band published for that state at the size this hardness calls for, equipment priced 2026-10-04 against the May 2025 reference period (OEWS M2025). Salt: the median retailer price of 3 retailers, read 2026-10-04, at a declared salt dose per regeneration. Drain water: about 50 gallons per regeneration from a government extension estimate read 2026-10-04, at the 2024 national average water and sewer rate from a government source read 2026-10-04.
Deciding whether it is worth it at all? Start from how much a water softener costs nationally — the same equipment, installation and ten-year ownership breakdown before any state wage adjustment is applied.
Maryland Cities by Hardness Category
Measured cities only — labeled county estimates never enter the category counts or the median.
| Category | Range | Measured cities | Share |
|---|---|---|---|
| Soft | 0-60 mg/L | 4 | 25.0% |
| Moderately hard | 60-120 mg/L | 8 | 50.0% |
| Hard | 120-180 mg/L | 4 | 25.0% |
| Very hard | >180 mg/L | 0 | 0.0% |
Hardest and Softest Water in Maryland
Measured values only; labeled county estimates and values under active dispute never rank.
Hardest water in Maryland
- Rockville — 141.0 mg/L (8.3 gpg), hard
- Urbana — 132.0 mg/L (7.7 gpg), hard
- Mount Airy — 131.0 mg/L (7.7 gpg), hard
- Chesapeake Beach — 130.0 mg/L (7.6 gpg), hard
- Takoma Park — 108.0 mg/L (6.3 gpg), moderately hard
Softest water in Maryland
- Easton — 23.6 mg/L (1.4 gpg), soft
- Severn — 26.9 mg/L (1.6 gpg), soft
- Salisbury — 32.3 mg/L (1.9 gpg), soft
- Severna Park — 34.6 mg/L (2.0 gpg), soft
- Columbia — 73.8 mg/L (4.3 gpg), moderately hard
Every Covered City in Maryland
All 137 covered Maryland cities, sorted by population served. "County estimate" rows are labeled context values from USGS/EPA Water Quality Portal county sampling — they never enter the median above. City names link to each city's full water quality page.
| City | Hardness (mg/L) | gpg | Category | Data |
|---|---|---|---|---|
| Takoma Park | 108.0 | 6.3 | Moderately hard | Utility-reported |
| Baltimore | 169.0 | 9.9 | Hard | County estimate |
| Severna Park | 34.6 | 2.0 | Soft | Utility-reported |
| Columbia | 73.8 | 4.3 | Moderately hard | Utility-reported |
| Abingdon | 80.9 | 4.7 | Moderately hard | County estimate |
| Bel Air | 81.0 | 4.7 | Moderately hard | Utility-reported |
| Bel Air South | 81.0 | 4.7 | Moderately hard | Utility-reported |
| Hagerstown | 126.0 | 7.4 | Hard | County estimate |
| Funkstown | 126.0 | 7.4 | Hard | County estimate |
| Lexington Park | 5.7 | 0.3 | Soft | County estimate |
| Odenton | 77.1 | 4.5 | Moderately hard | County estimate |
| Frederick | 105.0 | 6.1 | Moderately hard | Utility-reported |
| Rockville | 141.0 | 8.3 | Hard | Utility-reported |
| Urbana | 132.0 | 7.7 | Hard | Utility-reported |
| Aberdeen | 80.9 | 4.7 | Moderately hard | County estimate |
| California | 5.7 | 0.3 | Soft | County estimate |
| Salisbury | 32.3 | 1.9 | Soft | Utility-reported |
| Bowie | 78.1 | 4.6 | Moderately hard | Utility-reported |
| Fairwood | 78.1 | 4.6 | Moderately hard | Utility-reported |
| Sykesville | 62.0 | 3.6 | Moderately hard | County estimate |
| Westminster | 62.0 | 3.6 | Moderately hard | County estimate |
| Patuxent River | 5.7 | 0.3 | Soft | County estimate |
| Easton | 23.6 | 1.4 | Soft | Utility-reported |
| Havre de Grace | 80.9 | 4.7 | Moderately hard | County estimate |
| Cambridge | 57.1 | 3.3 | Soft | County estimate |
| Elkton | 94.0 | 5.5 | Moderately hard | County estimate |
| La Plata | 30.6 | 1.8 | Soft | County estimate |
| Mount Airy | 131.0 | 7.7 | Hard | Utility-reported |
| Lusby | 127.0 | 7.4 | Hard | County estimate |
| Dunkirk | 127.0 | 7.4 | Hard | County estimate |
| North East | 94.0 | 5.5 | Moderately hard | County estimate |
| Walkersville | 64.8 | 3.8 | Moderately hard | County estimate |
| Ocean City | 52.5 | 3.1 | Soft | County estimate |
| Brunswick | 64.8 | 3.8 | Moderately hard | County estimate |
| Perryville | 94.0 | 5.5 | Moderately hard | County estimate |
| Aberdeen Proving Ground | 80.9 | 4.7 | Moderately hard | County estimate |
| Fruitland | 30.7 | 1.8 | Soft | County estimate |
| Severn | 26.9 | 1.6 | Soft | Utility-reported |
| Chestertown | 60.6 | 3.5 | Moderately hard | County estimate |
| Poolesville | 84.2 | 4.9 | Moderately hard | Utility-reported |
| Chesapeake Beach | 130.0 | 7.6 | Hard | Utility-reported |
| Berlin | 52.5 | 3.1 | Soft | County estimate |
| Prince Frederick | 127.0 | 7.4 | Hard | County estimate |
| Pocomoke City | 52.5 | 3.1 | Soft | County estimate |
| Solomons | 127.0 | 7.4 | Hard | County estimate |
| Charlestown | 94.0 | 5.5 | Moderately hard | County estimate |
| Williamsport | 126.0 | 7.4 | Hard | County estimate |
| Snow Hill | 52.5 | 3.1 | Soft | County estimate |
| St. Michaels | 44.0 | 2.6 | Soft | County estimate |
| Centreville | 58.5 | 3.4 | Soft | County estimate |
| Princess Anne | 39.7 | 2.3 | Soft | County estimate |
| North Beach | 77.1 | 4.5 | Moderately hard | County estimate |
| Leonardtown | 5.7 | 0.3 | Soft | County estimate |
| Cumberland | 72.5 | 4.2 | Moderately hard | County estimate |
| Millersville | 77.1 | 4.5 | Moderately hard | County estimate |
| Smithsburg | 126.0 | 7.4 | Hard | County estimate |
| Federalsburg | 40.8 | 2.4 | Soft | County estimate |
| Stevensville | 58.5 | 3.4 | Soft | County estimate |
| Emmitsburg | 64.8 | 3.8 | Moderately hard | County estimate |
| Westernport | 89.4 | 5.2 | Moderately hard | County estimate |
| Hurlock | 57.1 | 3.3 | Soft | County estimate |
| Perry Point | 94.0 | 5.5 | Moderately hard | County estimate |
| Hancock | 126.0 | 7.4 | Hard | County estimate |
| Greensboro | 40.8 | 2.4 | Soft | County estimate |
| Rock Hall | 60.6 | 3.5 | Moderately hard | County estimate |
| Ridgely | 40.8 | 2.4 | Soft | County estimate |
| Myersville | 64.8 | 3.8 | Moderately hard | County estimate |
| Pittsville | 30.7 | 1.8 | Soft | County estimate |
| Trappe | 44.0 | 2.6 | Soft | County estimate |
| Grasonville | 58.5 | 3.4 | Soft | County estimate |
| New Windsor | 62.0 | 3.6 | Moderately hard | County estimate |
| Hebron | 30.7 | 1.8 | Soft | County estimate |
| Oakland | 89.4 | 5.2 | Moderately hard | County estimate |
| Willards | 30.7 | 1.8 | Soft | County estimate |
| Denton | 40.8 | 2.4 | Soft | County estimate |
| Savage | 60.1 | 3.5 | Moderately hard | County estimate |
| Crofton | 77.1 | 4.5 | Moderately hard | County estimate |
| Oxford | 44.0 | 2.6 | Soft | County estimate |
| Queenstown | 58.5 | 3.4 | Soft | County estimate |
| Preston | 40.8 | 2.4 | Soft | County estimate |
| Chesapeake City | 94.0 | 5.5 | Moderately hard | County estimate |
| Lothian | 77.1 | 4.5 | Moderately hard | County estimate |
| Secretary | 57.1 | 3.3 | Soft | County estimate |
| East New Market | 57.1 | 3.3 | Soft | County estimate |
| Kitzmiller | 89.4 | 5.2 | Moderately hard | County estimate |
| St. Leonard | 127.0 | 7.4 | Hard | County estimate |
| Huntingtown | 127.0 | 7.4 | Hard | County estimate |
| Accident | 89.4 | 5.2 | Moderately hard | County estimate |
| Delmar | 30.7 | 1.8 | Soft | County estimate |
| Conowingo | 94.0 | 5.5 | Moderately hard | County estimate |
| St. James | 126.0 | 7.4 | Hard | County estimate |
| Port Deposit | 94.0 | 5.5 | Moderately hard | County estimate |
| Bishopville | 52.5 | 3.1 | Soft | County estimate |
| Libertytown | 64.8 | 3.8 | Moderately hard | County estimate |
| Hollywood | 5.7 | 0.3 | Soft | County estimate |
| Jessup | 60.1 | 3.5 | Moderately hard | County estimate |
| Towson | 216.0 | 12.6 | Very hard | County estimate |
| Sunderland | 127.0 | 7.4 | Hard | County estimate |
| Waldorf | 30.6 | 1.8 | Soft | County estimate |
| Queen Anne | 58.5 | 3.4 | Soft | County estimate |
| Cordova | 44.0 | 2.6 | Soft | County estimate |
| Chester | 58.5 | 3.4 | Soft | County estimate |
| Swanton | 89.4 | 5.2 | Moderately hard | County estimate |
| Church Hill | 58.5 | 3.4 | Soft | County estimate |
| Beltsville | 112.0 | 6.5 | Moderately hard | County estimate |
| Bethesda | 145.5 | 8.5 | Hard | County estimate |
| Bladensburg | 112.0 | 6.5 | Moderately hard | County estimate |
| Brentwood | 112.0 | 6.5 | Moderately hard | County estimate |
| Brookeville | 145.5 | 8.5 | Hard | County estimate |
| Burtonsville | 145.5 | 8.5 | Hard | County estimate |
| Cabin John | 145.5 | 8.5 | Hard | County estimate |
| Capitol Heights | 112.0 | 6.5 | Moderately hard | County estimate |
| Chevy Chase | 145.5 | 8.5 | Hard | County estimate |
| Cockeysville | 216.0 | 12.6 | Very hard | County estimate |
| College Park | 112.0 | 6.5 | Moderately hard | County estimate |
| Derwood | 145.5 | 8.5 | Hard | County estimate |
| District Heights | 112.0 | 6.5 | Moderately hard | County estimate |
| Ellicott City | 60.1 | 3.5 | Moderately hard | County estimate |
| Gaithersburg | 145.5 | 8.5 | Hard | County estimate |
| Garrett Park | 145.5 | 8.5 | Hard | County estimate |
| Glen Echo | 145.5 | 8.5 | Hard | County estimate |
| Greenbelt | 112.0 | 6.5 | Moderately hard | County estimate |
| Hyattsville | 112.0 | 6.5 | Moderately hard | County estimate |
| Kensington | 145.5 | 8.5 | Hard | County estimate |
| Lanham | 112.0 | 6.5 | Moderately hard | County estimate |
| Laurel | 112.0 | 6.5 | Moderately hard | County estimate |
| Mount Rainier | 112.0 | 6.5 | Moderately hard | County estimate |
| Olney | 145.5 | 8.5 | Hard | County estimate |
| Oxon Hill | 112.0 | 6.5 | Moderately hard | County estimate |
| Port Republic | 127.0 | 7.4 | Hard | County estimate |
| Potomac | 145.5 | 8.5 | Hard | County estimate |
| Silver Spring | 145.5 | 8.5 | Hard | County estimate |
| Spencerville | 145.5 | 8.5 | Hard | County estimate |
| Suitland | 112.0 | 6.5 | Moderately hard | County estimate |
| Temple Hills | 112.0 | 6.5 | Moderately hard | County estimate |
| Union Bridge | 64.8 | 3.8 | Moderately hard | County estimate |
| Washington Grove | 145.5 | 8.5 | Hard | County estimate |
Above 120 mg/L (7 gpg), scale is usually worth treating — see our water softener guide, or size a system with the hardness calculator & converter.
The Geology Behind Maryland's Water Hardness
Maryland sits in the Appalachian and Mid-Atlantic mixed terrain region.
The Mid-Atlantic and Appalachian states sit on a patchwork of sandstone, shale, and crystalline rock that yields mostly soft to moderately hard water. The big exception is the region's limestone and dolomite valleys - including the carbonate belt running from Pennsylvania down through the Shenandoah Valley - where groundwater dissolves calcium and magnesium readily and comes out distinctly hard. A city's number here depends heavily on whether its supply draws from upland rivers and reservoirs or from carbonate-valley wells.
Maryland Water Hardness FAQ
Does Maryland have hard water?
On the whole, no — Maryland's statewide median sits below the hard threshold, though some cities run harder. The median is 81.0 mg/L (4.7 gpg) — moderately hard on the USGS scale, where anything above 120 mg/L (7 gpg) counts as hard. 4 of Maryland's 16 measured cities fall in the hard or very hard bands (25%), so check your own city rather than the state average.
How hard is tap water in Maryland?
Across the 16 Maryland cities with measured values in our index, the median hardness is 81.0 mg/L (4.7 gpg) — moderately hard on the USGS scale. Individual cities range from 23.6 to 141.0 mg/L, so check your own city rather than assuming the state number.
Which city in Maryland has the hardest water?
Rockville has the hardest measured tap water in our Maryland index at 141.0 mg/L (8.3 gpg) — hard on the USGS scale. Rankings use measured utility values only; labeled county estimates and values under active dispute are excluded.
Do I need a water softener in Maryland?
4 of Maryland's 16 measured cities (25%) fall in the hard or very hard bands — above 120 mg/L (7 gpg), the level where most water treatment professionals suggest considering an ion-exchange softener. Hardness varies utility to utility, so look up your own city's value before sizing equipment.
How do I find my city's exact water hardness?
Enter your ZIP code in our free lookup at tapwaterdata.com/zip to see the value we hold for your Maryland city from utility-reported water quality data, check your water utility's annual Consumer Confidence Report (CCR), or use a home test-strip kit.
Need whole-house or professional water treatment?
For the problems a pitcher or under-sink filter cannot fix — scale, rust and black staining, sulfur smell, well contamination, or test results you cannot explain. Tell us what is happening and we will connect you with a local water-treatment professional.
Get the Weekly Water Brief
One email a week on water testing, treatment, and what water-quality data means for your home.
One email a week. Unsubscribe anytime.