South Yarmouth Water Hardness & Quality Report (2026)
Water Hardness
2.5 grains per gallon
Source
reservoir
pH Level
7.3
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
76.6 mg/L
Est. Daily Cost
$0.11
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 South Yarmouth, your appliances are currently losing 6% efficiency due to mineral buildup.
| Appliance | In South Yarmouth | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 8.2 yrs | 8.5 yrs | -4% |
| Washing Machine | 12 yrs | 12 yrs | — |
| Water Heater | 13.9 yrs | 15 yrs | -7% |
Regional Water Comparison
How South Yarmouth compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ South Yarmouth, Massachusetts | 43 mg/L | 6.1 ppt | 🟢 Soft | reservoir |
| Yarmouth, Massachusetts | 26 mg/L | 4.9 ppt | 🟢 Soft | reservoir |
| Hyannis, Massachusetts | 105.5 mg/L | 10.4 ppt | 🟡 Moderately Hard | reservoir |
| Harwich, Massachusetts | 56.5 mg/L | 7 ppt | 🟢 Soft | reservoir |
| Barnstable, Massachusetts | 101.5 mg/L | 10.2 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How South Yarmouth compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ South Yarmouth | 43 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes South Yarmouth's Water Unique?
Local geology and source profile
South Yarmouth, Massachusetts, in Barnstable County — a Barnstable County village in Yarmouth adjacent to Hyannis and West Yarmouth on Cape Cod — receives its water from the Yarmouth Division of Public Works, drawing from the Cape Cod Aquifer through the Cape Cod distribution.
The very soft 43 mg/L hardness and low TDS of 76.6 mg/L reflect the Barnstable County Cape Cod Aquifer supply's very soft character — the Pleistocene Cape Cod glacial outwash and Cretaceous Masthead Sand are both highly insoluble quartz sand and gravel formations contributing negligible dissolved minerals to the pristine Cape Cod freshwater lens (compare Hyannis MA: 41/72 in Barnstable County comparable; West Yarmouth MA: 44/80 in Barnstable County comparable; South Yarmouth consistent very soft from the same Barnstable County Cape Cod Aquifer Pleistocene glacial supply). The Cape Cod Aquifer — Pleistocene Cape Cod glacial outwash (insoluble — primary dilutant), Cretaceous Masthead Sand (insoluble — secondary dilutant), and Quaternary Cape Cod sediment (slightly calcareous — minimal TDS).
At 43 mg/L with TDS 77, South Yarmouth's water is very soft — virtually no scale buildup. Soft water can be mildly corrosive — check for blue-green copper staining in older plumbing. The PFAS level of 6.1 ppt warrants a certified drinking water filter. Review the Town of Yarmouth's annual water quality report.
Geology & Source: South Yarmouth in Barnstable County draws from the Yarmouth Water on the Cape Cod Aquifer (Barnstable County, Cape Cod, Massachusetts) — the Cape Cod aquifer draws from Pleistocene Cape Cod glacial outwash (insoluble) and Cretaceous Masthead Sand (insoluble) — Massachusetts Barnstable County Cape Cod Aquifer Pleistocene glacial supply produces very soft water at 43 mg/L with TDS 76.6 mg/L.