Fairfax Water Hardness & Quality Report (2026)
Water Hardness
6.1 grains per gallon
Source
reservoir
pH Level
7.6
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
185.3 mg/L
Est. Daily Cost
$0.28
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 Fairfax, your appliances are currently losing 14% efficiency due to mineral buildup.
| Appliance | In Fairfax | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.1 yrs | 8.5 yrs | -28% |
| Washing Machine | 9.7 yrs | 12 yrs | -19% |
| Water Heater | 11.4 yrs | 15 yrs | -24% |
Regional Water Comparison
How Fairfax compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Fairfax, Virginia | 105 mg/L | 5.3 ppt | 🟡 Moderately Hard | reservoir |
| Kings Park West, Virginia | 119.5 mg/L | 6.1 ppt | 🟡 Moderately Hard | reservoir |
| Oakton, Virginia | 147 mg/L | 7.6 ppt | 🟠 Hard | reservoir |
| Burke, Virginia | 89 mg/L | 4.5 ppt | 🟡 Moderately Hard | reservoir |
| Vienna, Virginia | 85.5 mg/L | 4.3 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Fairfax compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Fairfax | 105 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Fairfax's Water Unique?
Local geology and source profile
Fairfax, Virginia, an independent city in Northern Virginia near George Mason University and the Fairfax County Government Center, receives its municipal water from the City of Fairfax Water Division, which purchases supply from Fairfax Water — the regional utility drawing from Occoquan Reservoir (impounded on Bull Run in Prince William County) and supplementary supply from the Potomac River via Griffith Water Treatment Plant. Fairfax City receives water from the Occoquan-dominant service zone of Fairfax Water's distribution system.
The moderately soft 105 mg/L hardness and low TDS of 185.3 mg/L reflect the Occoquan Reservoir's Piedmont Province watershed character — the dominant source for this portion of Fairfax Water's service area. Bull Run and its tributaries drain the Northern Virginia Piedmont over ancient Precambrian Grenville-age gneisses, Paleozoic metavolcanic and metasedimentary rocks, and the Triassic Newark Basin (Manassas sandstone) — terrains with very limited carbonate content. Occoquan Reservoir water is softer than Potomac River water, and the Fairfax City service zone receives a higher proportion of the softer Occoquan supply.
At 105 mg/L, Fairfax's water is moderately soft — comfortable for everyday household use in this government services community. Scale forms gradually in kettles and appliances over several months, soap lathers well, and the dishwasher produces clean results without special treatment. Semi-annual descaling of heating appliances is adequate. The PFAS level of 5.3 ppt is favorable for a Northern Virginia community — Fairfax City's relatively contained urban footprint near George Mason University and government office parks keeps PFAS contributions below the elevated levels seen in adjacent military and industrial corridor communities.
Geology & Source: Fairfax in the City of Fairfax is served by Fairfax Water drawing from Occoquan Reservoir on the Bull Run watershed — Occoquan's watershed drains the Virginia Piedmont Province over Precambrian and Paleozoic metamorphic rocks with limited carbonate contact — Piedmont reservoir drainage produces moderately soft water at 105 mg/L, one of the softer supplies in the Fairfax Water service area.