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

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

Arlington Water Hardness & Quality Report (2026)

Water Hardness

soft

~0–59 mg/L

Soft

estimated · not lab-verified

Source

reservoir

pH Level

7.6

neutral = 7.0

Lead

0.005 mg/L

✓ Below action level

TDS

166.6 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 Arlington, your appliances are currently losing 4% efficiency due to mineral buildup.

Appliance	In Arlington	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 Arlington compares to its nearest neighbours

City	Hardness	Risk	Source
▶ Arlington, Massachusetts	≈ 0–59 mg/L	🟢 Soft	reservoir
Belmont, Massachusetts	17.5 mg/L	🟢 Soft	reservoir
Winchester, Massachusetts	≈ 0–60 mg/L	🟢 Soft	reservoir
Medford, Massachusetts	≈ 0–60 mg/L	🟢 Soft	reservoir
Watertown, Massachusetts	≈ 0–60 mg/L	🟢 Soft	reservoir

National Benchmark

How Arlington compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Arlington	≈ 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 Arlington's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 166.6 mg/LpH: 7.6

The Arlington Water Department, part of the Massachusetts Water Resources Authority (MWRA) system, serves the town of Arlington in Middlesex County, Massachusetts, with a population of approximately 45,000. Water is sourced exclusively from the Quabbin Reservoir, New England's largest inland water body, supplemented by the Wachusett Reservoir. Treatment occurs at the John J. Carroll Water Treatment Plant in Marlborough, MA, employing ozonation, chloramination, and corrosion control before distribution through 120 miles of mains to residential and commercial customers.

The Quabbin Reservoir lies within the 120-square-mile Ware River Watershed, protected by strict land-use regulations including 68% forest cover. Underlying geology features metamorphosed sedimentary rocks such as the Worcester Phyllite and igneous intrusives from the Devonian to Carboniferous periods, with no significant limestone formations. This crystalline bedrock yields very soft water with low alkalinity and dissolved solids, as granite and schist resist mineral release compared to carbonate terrains.

As a soft water supply, scale buildup is negligible, sparing appliances like water heaters, dishwashers, and coffee makers from calcification. Soap lathers easily without excess detergent, and laundry feels cleaner. No water softener is needed or recommended; instead, monitor for corrosion risks in pipes and use phosphate additives for protection. MWRA water maintains a pH of around 9–10 due to lime addition; lead 90th percentile was 1.39 ppb (action level 15 ppb) and copper 81.6 ppb (action level 1,300 ppb), both compliant, with no recent PFAS exceedances reported.

Geology & Source: Quabbin Reservoir, Ware River Watershed — Paleozoic schists, gneisses, and granites of the Appalachian geosyncline overlain by glacial till; low-carbonate crystalline bedrock yields characteristically soft, low-mineral water

Other Massachusetts Water Reports

Belmont

17.5 mg/L

🟢 Soft

Winchester

≈ 0–60 mg/L

🟢 Soft

Medford

≈ 0–60 mg/L

🟢 Soft

Watertown

≈ 0–60 mg/L

🟢 Soft

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Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.

All reports are reviewed by our team. Thank you for supporting data quality!

Frequently Asked Questions

Is Arlington's water safe to drink?

Yes. Arlington'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 Arlington?

Arlington'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 Arlington compare to the USA average?

The USA national average is 151 mg/L. Arlington (≈ 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 Arlington 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.