How does Hyannis's water compare to the national average?

The USA national average is 151 mg/L. Hyannis (≈ 0–59 mg/L) is 121 mg/L softer than average.

Hyannis Water Hardness & Quality Report (2026)

Water Hardness

soft

~0–59 mg/L

Soft

estimated · not lab-verified

Source

groundwater

pH Level

7.8

neutral = 7.0

Lead

0.008 mg/L

✓ Below action level

TDS

262.1 mg/L

Est. Daily Cost

$0.08

energy & soap waste

Source: See methodology section below · Updated 2026

soft~0–59 mg/LSoft · est.

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 4% efficiency due to mineral buildup.

Appliance	In Hyannis	Soft Water City	Efficiency Loss
Kettle	8.2 yrs	8.5 yrs	-4%
Washing Machine	11.5 yrs	12 yrs	-4%
Water Heater	14.4 yrs	15 yrs	-4%

Regional Water Comparison

How Hyannis compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Hyannis, Massachusetts	≈ 0–59 mg/L	107.8 ppt	🟢 Soft	groundwater
Barnstable, Massachusetts	≈ 0–60 mg/L	69.6 ppt	🟢 Soft	groundwater
Yarmouth, Massachusetts	≈ 0–60 mg/L	219.1 ppt	🟢 Soft	groundwater
South Yarmouth, Massachusetts	≈ 0–60 mg/L	6.1 ppt	🟢 Soft	groundwater
Mashpee, Massachusetts	≈ 120–179 mg/L	8 ppt	🟠 Hard	groundwater

National Benchmark

How Hyannis compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Hyannis	≈ 0–59 mg/L	🟢 None
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

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What Makes Hyannis's Water Unique?

Local geology and source profile

Source: GroundwaterTDS: 262.1 mg/LpH: 7.8

The Hyannis Water System, part of the Town of Barnstable Water Supply Department, provides drinking water to about 15,000 residents in the Hyannis area of Barnstable County, Cape Cod, Massachusetts. Their water comes exclusively from groundwater wells that draw from the Sagamore and Monomoy aquifers, which are part of the Cape Cod groundwater system. Treatment is minimal, occurring at wellhead facilities where disinfection with chlorine is applied. No surface water sources like reservoirs or rivers are used for the supply.

The Hyannis water originates from the Sagamore Aquifer and Monomoy Aquifer, formations consisting of unconsolidated glacial deposits from the Pleistocene epoch. These sediments, primarily sands and gravels, were laid down as the Laurentide Ice Sheet retreated. This geology, situated over the Buzzards Bay Moraine, means the water has very low mineral content. Because the water primarily percolates through quartz-rich sands and lacks contact with limestone or dolomite bedrock, it remains exceptionally soft.

Homeowners in Hyannis will notice that this very soft water causes minimal scale buildup on appliances like water heaters and dishwashers, and also on pipes. You won't need to worry about the excessive use of soap or detergents, as they lather easily. While softening isn't necessary, very soft water can sometimes lead to increased corrosion in metal plumbing if the pH is low. It's a good idea to watch for any blue staining on fixtures, which could indicate copper corrosion, and to have galvanized pipes checked annually.

Geology & Source: Sagamore Aquifer and Monomoy Aquifer; unconsolidated Pleistocene glacial deposits of sand and gravel yield very soft water due to limited contact with limestone or dolomite

Other Massachusetts Water Reports

Barnstable

≈ 0–60 mg/L

🟢 Soft

Yarmouth

≈ 0–60 mg/L

🟢 Soft

South Yarmouth

≈ 0–60 mg/L

🟢 Soft

Mashpee

≈ 120–179 mg/L

🟠 Hard

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Frequently Asked Questions

Is Hyannis's water safe to drink?

Yes. Hyannis's water meets all federal safety standards. The hardness is ≈ 0–59 mg/L (Soft), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Hyannis?

Hyannis's water is soft at ≈ 0–59 mg/L. A water softener is generally not necessary, though a carbon filter can improve taste and remove any remaining chlorine.

How does Hyannis compare to the USA average?

The USA national average is 151 mg/L. Hyannis (≈ 0–59 mg/L) is 121 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Hyannis is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

Water Hardness

Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

TDS — Total Dissolved Solids

Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.

Measured

PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances

EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.

Modelled

Lead

Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.

Calculated

Appliance Lifespan

Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.