Water hardness in Greenbelt
6 gpg moderately hard
Tap water in Greenbelt is moderately hard: 6 gpg (103 mg/L · 5.7 °dH · 10.3 °fH).
Source: WSSC Water Tap Water Analysis 2023 (Potomac and Patuxent) (2023) · data checked 2026-11-02
Range across supply zones: 53–195 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| Patuxent Water Filtration Plant | 3.8 | 65 | moderately hard |
| Potomac Water Filtration Plant | 8.2 | 140 | hard |
Greenbelt is served by WSSC Water, whose 2023 tap report covers the Potomac and Patuxent systems. Hardness runs from 53 to 195 mg/L as CaCO3, with a median of 102.5 mg/L across two zones. Which zone you are in decides where you fall in that range.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 6 gpg |
|---|---|
| Calcium (mg/L) | 17.5 |
| Utility | WSSC Water |
How Greenbelt compares
- Tap water in Greenbelt is 34 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1004 of 1372 in the United States (1 = hardest); 27 % of these cities have softer water.
- In Maryland it is number 3 of 6 cities; the regional median is 5.8 gpg.
Ranking of the hardest and softest water in the United States →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Greenbelt
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Greenbelt water hard or soft?
It is moderately hard: 103 mg/L as CaCO₃ (6 gpg, 5.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Greenbelt safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is Greenbelt water?
6 gpg, equal to 5.7 °dH, 10.3 °fH or 103 mg/L calcium carbonate.
What dishwasher salt setting should I use in Greenbelt?
For 103 mg/L (5.7 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Greenbelt?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: WSSC Water Tap Water Analysis 2023 (Potomac and Patuxent) (2023). Method: figure published by the water supplier. WSSC Water Tap Water Analysis 2023 (Potomac and Patuxent) · Outdated figure? Tell us