Chantilly Water Hardness & Quality Report (2026)
Water Hardness
10.7 grains per gallon
Source
reservoir
pH Level
8.3
neutral = 7.0
Lead
0.008 mg/L
✓ Below action level
TDS
465 mg/L
Est. Daily Cost
$0.49
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 Chantilly, your appliances are currently losing 24% efficiency due to mineral buildup.
| Appliance | In Chantilly | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 3.5 yrs | 8.5 yrs | -59% |
| Washing Machine | 6.8 yrs | 12 yrs | -43% |
| Water Heater | 8.3 yrs | 15 yrs | -45% |
Regional Water Comparison
How Chantilly compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Chantilly, Virginia | 183.5 mg/L | 9.5 ppt | 🔴 Very Hard | reservoir |
| Oak Hill, Virginia | 114.5 mg/L | 5.8 ppt | 🟡 Moderately Hard | reservoir |
| Centreville, Virginia | 178.5 mg/L | 9.3 ppt | 🟠 Hard | reservoir |
| South Riding, Virginia | 117 mg/L | 6 ppt | 🟡 Moderately Hard | reservoir |
| Herndon, Virginia | 134 mg/L | 6.9 ppt | 🟠 Hard | reservoir |
National Benchmark
How Chantilly compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Chantilly | 183.5 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
Bring Badger-quality water to your Chantilly home
Shop water softeners on Amazon.com →
What Makes Chantilly's Water Unique?
Local geology and source profile
Chantilly, Virginia, in Fairfax County in the western Dulles Technology Corridor near Washington Dulles International Airport — a major Northern Virginia technology hub with dense corporate campuses for SAIC, Northrop Grumman, and numerous defense contractors — receives its municipal water from Fairfax Water, which draws from the Potomac River at the Griffith Water Treatment Plant in Great Falls and the Occoquan Reservoir on Bull Run. Chantilly's western Fairfax County position in the Dulles corridor places it primarily in Fairfax Water's Potomac River-dominant service zone.
The moderately hard 183.5 mg/L hardness and elevated TDS of 465 mg/L are notably harder than inner Fairfax County communities (Baileys Crossroads 112 mg/L, Fairfax City 105 mg/L) that receive more Occoquan Reservoir supply, reflecting Chantilly's greater dependence on Potomac River water from the Griffith plant. The Potomac at Great Falls carries substantial carbonate hardness from its upper basin's Valley and Ridge Province tributaries — the Shenandoah River (draining Ordovician Newmarket and Edinburg limestones), Conococheague Creek (Cambrian Conococheague Formation carbonates), and other Valley and Ridge streams that substantially raise Potomac hardness relative to the softer Occoquan Reservoir.
At 183.5 mg/L, Chantilly's water is moderately hard — harder than many Northern Virginia communities due to the Potomac River influence. Scale builds in kettles and coffee machines within weeks to months, dishwashers benefit from rinse aid, and bathroom fixtures develop calcium deposits. Quarterly descaling of heating appliances is the standard schedule. The elevated PFAS level of 9.5 ppt reflects Chantilly's proximity to Dulles Airport and the dense defense contractor campus environment — aviation, aerospace, and defense technology industries in the Dulles corridor are recognized contributors to elevated PFAS in western Fairfax County groundwater and the regional water supply. A certified drinking water filter is strongly recommended.
Geology & Source: Chantilly in Fairfax County is served by Fairfax Water drawing predominantly from the Potomac River at the Griffith Water Treatment Plant — the Potomac's Valley and Ridge tributaries (Shenandoah, Conococheague) drain Ordovician and Cambrian carbonate formations — carbonate-rich Potomac basin drainage dominates the western Fairfax County supply, producing hard water at 183.5 mg/L with TDS 465 mg/L.