Largo Water Hardness & Quality Report (2026)
Water Hardness
5.3 grains per gallon
Source
reservoir
pH Level
7.5
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
146.6 mg/L
Est. Daily Cost
$0.24
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Largo, your appliances are currently losing 12% efficiency due to mineral buildup.
| Appliance | In Largo | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.6 yrs | 8.5 yrs | -22% |
| Washing Machine | 10.3 yrs | 12 yrs | -14% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Largo compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Largo, Maryland | 90.5 mg/L | 4.8 ppt | 🟡 Moderately Hard | reservoir |
| Kettering, Maryland | 190 mg/L | 10.4 ppt | 🔴 Very Hard | reservoir |
| Mitchellville, Maryland | 199 mg/L | 10.9 ppt | 🔴 Very Hard | reservoir |
| Summerfield, Maryland | 113 mg/L | 6.1 ppt | 🟡 Moderately Hard | reservoir |
| Walker Mill, Maryland | 183.5 mg/L | 10 ppt | 🔴 Very Hard | reservoir |
National Benchmark
How Largo compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Largo | 90.5 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Largo's Water Unique?
Local geology and source profile
Largo, Maryland, in Prince George's County — a Prince George's County unincorporated community adjacent to Upper Marlboro and Bowie in the DC Maryland suburbs — receives its water from WSSC Water, drawing from the Patuxent River through the central Maryland distribution.
The moderately hard 90.5 mg/L hardness and TDS of 146.6 mg/L reflect the Prince George's County supply's moderate Coastal Plain character — the Cretaceous Patuxent Formation and Precambrian Baltimore Gneiss are largely insoluble formations contributing minimal dissolved mineral content; WSSC's treatment process brings these values into the moderate range (compare Upper Marlboro MD: 87/140 in Prince George's County comparable; Bowie MD: 92/153 in Prince George's County comparable; Largo consistent moderate from the same Prince George's County Patuxent River Cretaceous supply). The Patuxent watershed — Cretaceous Patuxent Formation (insoluble — primary dilutant), Precambrian Baltimore Gneiss (insoluble — secondary dilutant), and Quaternary Coastal Plain alluvium (slightly calcareous — TDS contributor).
At 90.5 mg/L with TDS 147, Largo's water is moderately hard — mild scale buildup. Semi-annual descaling is appropriate. The PFAS level of 4.8 ppt is moderate — a certified drinking water filter provides added protection. Review WSSC Water's annual water quality report.
Geology & Source: Largo in Prince George's County draws from the WSSC Water on the Patuxent River supply (Prince George's County, central Maryland) — the Patuxent watershed draws from Cretaceous Patuxent Formation (insoluble) and Precambrian Baltimore Gneiss (insoluble) — Maryland Prince George's County Patuxent River Cretaceous supply produces moderately hard water at 90.5 mg/L with TDS 146.6 mg/L.