Hyannis Water Hardness & Quality Report (2026)
Water Hardness
6.2 grains per gallon
Source
reservoir
pH Level
7.8
neutral = 7.0
Lead
0.008 mg/L
✓ Below action level
TDS
262.1 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 Hyannis, your appliances are currently losing 14% efficiency due to mineral buildup.
| Appliance | In Hyannis | 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 Hyannis compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Hyannis, Massachusetts | 105.5 mg/L | 10.4 ppt | 🟡 Moderately Hard | reservoir |
| Barnstable, Massachusetts | 101.5 mg/L | 10.2 ppt | 🟡 Moderately Hard | reservoir |
| Yarmouth, Massachusetts | 26 mg/L | 4.9 ppt | 🟢 Soft | reservoir |
| Mashpee, Massachusetts | 20.5 mg/L | 4.5 ppt | 🟢 Soft | reservoir |
| Harwich, Massachusetts | 56.5 mg/L | 7 ppt | 🟢 Soft | reservoir |
National Benchmark
How Hyannis compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Hyannis | 105.5 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Hyannis's Water Unique?
Local geology and source profile
Hyannis, Massachusetts, in Barnstable County — the Barnstable County seat on Cape Cod adjacent to Barnstable and Yarmouth in southeast Massachusetts — receives its water from the Barnstable Water Company, drawing from the Cape Cod aquifer (Barnstable County) through the Cape Cod distribution.
The moderately hard 105.5 mg/L hardness and TDS of 262.1 mg/L are harder than many other Cape Cod communities — reflecting the Hyannis commercial corridor's more developed distribution zone drawing from the more mineralized parts of the Cape Cod glaciofluvial outwash aquifer with slightly more calcareous shell fragment and Buzzards Bay Moraine till dissolution. The Cape Cod aquifer at Barnstable County is developed in Pleistocene glaciofluvial outwash sand (slightly calcareous — primary supply), Pleistocene Buzzards Bay Moraine (calcareous — primary hardness contributor from glacial carbonate till), and Holocene saltmarsh/coastal deposits (slightly brackish — elevated TDS).
At 105.5 mg/L, Hyannis' water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 10.4 ppt warrants a certified reverse osmosis drinking water filter — Cape Cod Air Force Station (Bourne, Barnstable County — AFFF) and the Barnstable County Superfund sites contribute significantly to Hyannis' elevated readings.
Geology & Source: Hyannis in Barnstable County draws from the Barnstable Water Company on the Hyannis Water System groundwater (Barnstable County, southeast Massachusetts Cape Cod) — the Cape Cod aquifer is developed in Pleistocene glaciofluvial outwash sand (slightly calcareous) and Pleistocene Buzzards Bay Moraine — Massachusetts Barnstable County Cape Cod Pleistocene glaciofluvial outwash aquifer produces moderately hard water at 105.5 mg/L with TDS 262.1 mg/L.