Downtown DC Water Hardness & Quality Report (2026)
Water Hardness
6.6 grains per gallon
Source
river
pH Level
7.8
neutral = 7.0
Lead
0.006 mg/L
✓ Below action level
TDS
253.1 mg/L
Est. Daily Cost
$0.30
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 Downtown DC, your appliances are currently losing 15% efficiency due to mineral buildup.
| Appliance | In Downtown DC | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.9 yrs | 8.5 yrs | -31% |
| Washing Machine | 9.4 yrs | 12 yrs | -22% |
| Water Heater | 11.1 yrs | 15 yrs | -26% |
Regional Water Comparison
How Downtown DC compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Downtown DC, District of Columbia | 113 mg/L | 7.5 ppt | 🟡 Moderately Hard | river |
| Mount Vernon Triangle, District of Columbia | 113 mg/L | 7.5 ppt | 🟡 Moderately Hard | river |
| Northwest One, District of Columbia | 113.5 mg/L | 7.5 ppt | 🟡 Moderately Hard | river |
| Southwest Waterfront, District of Columbia | 113.5 mg/L | 7.5 ppt | 🟡 Moderately Hard | river |
| Washington, District of Columbia | 75.5 mg/L | 4.1 ppt | 🟡 Moderately Hard | river |
National Benchmark
How Downtown DC compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Downtown DC | 113 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Downtown DC's Water Unique?
Local geology and source profile
Downtown Washington, DC — the central business and government district of the nation's capital, encompassing the National Mall, federal office buildings, and the historic Penn Quarter–Chinatown–K Street corridor — receives its municipal water supply from the Potomac River via the Washington Aqueduct (US Army Corps of Engineers) and the DC Water and Sewer Authority (DC Water). Water hardness in Downtown DC measures 113 mg/L — classified as moderately hard.
Downtown DC's moderate hardness reflects the Potomac River's Maryland–Virginia Piedmont watershed. The Potomac River above Great Falls–Washington drains: the Maryland and Virginia Piedmont crystalline belt (Catoctin Formation metavolcanic greenstone of the Blue Ridge, Wissahickon Formation phyllite and mica schist — moderate calcareous content); the Valley and Ridge Province (Silurian–Devonian calcareous limestone of the Shenandoah Valley — some calcareous contribution dissolved in the South Branch and North Branch Potomac tributaries). DC Water's McMillan Sand Filtration Site and Dalecarlia Water Treatment Plant apply effective modern treatment including coagulation, filtration, and disinfection, producing the moderate 113 mg/L at the downtown DC tap.
At 113 mg/L, Downtown DC residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. DC Water consistently delivers water meeting all DC DOH and EPA Safe Drinking Water Act requirements.
Geology & Source: River supply from the Potomac River via the Washington Aqueduct (US Army Corps of Engineers) and the DC Water and Sewer Authority (DC Water) — the Maryland–Virginia Piedmont crystalline belt Potomac River watershed; moderately hard supply at 113 mg/L — reflecting DC Water's modern treatment of the Potomac supply and the downtown Washington distribution zone.