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

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

Waltham Water Hardness & Quality Report (2026)

Water Hardness

soft

~0–59 mg/L

Soft

estimated · not lab-verified

Source

reservoir

pH Level

7.4

neutral = 7.0

Lead

0.004 mg/L

✓ Below action level

TDS

97.9 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 Waltham, your appliances are currently losing 4% efficiency due to mineral buildup.

Appliance	In Waltham	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 Waltham compares to its nearest neighbours

City	Hardness	Risk	Source
▶ Waltham, Massachusetts	≈ 0–59 mg/L	🟢 Soft	reservoir
Newtonville, Massachusetts	≈ 0–60 mg/L	🟢 Soft	reservoir
Newton, Massachusetts	≈ 0–60 mg/L	🟢 Soft	reservoir
Watertown, Massachusetts	≈ 0–60 mg/L	🟢 Soft	reservoir
Belmont, Massachusetts	17.5 mg/L	🟢 Soft	reservoir

National Benchmark

How Waltham compares to the USA average

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

Local geology and source profile

Source: ReservoirTDS: 97.9 mg/LpH: 7.4

The Waltham Water Department serves approximately 61,154 residents in Waltham, Massachusetts, in Middlesex County. Water is purchased from the Massachusetts Water Resources Authority (MWRA) and sourced from the Quabbin Reservoir and Wachusett Reservoir in central Massachusetts. Treatment occurs at MWRA facilities, including the John J. Carroll Water Treatment Plant and the Norumbega Covered Storage Facility, before distribution through the Waltham Water Department at 610 Main Street.

The supply originates from the Quabbin-Wachusett watershed in central Massachusetts, encompassing protected forested lands overlying Paleozoic metamorphic bedrock — primarily gneiss and schist. Glacial deposits influence surficial hydrology, but the reservoirs yield very soft water due to short rock-water interaction in granitic terrains. Surface water collection over these crystalline, low-carbonate formations produces characteristically low-mineralized chemistry typical of New England surface supplies, with minimal dissolved calcium and magnesium.

As soft water, Waltham's supply causes negligible scale buildup, posing no risk to pipes, water heaters, dishwashers, or washing machines. Soap lathers easily, and laundry remains bright without excess detergent. No water softener is needed or recommended; standard maintenance suffices, avoiding unnecessary sodium addition. MWRA water undergoes ozonation, chloramination, and fluoridation, with pH typically 8.5–9.5 for corrosion control. The Waltham Water Department reports consistent compliance with lead and copper action levels under the Safe Drinking Water Act.

Geology & Source: Quabbin and Wachusett Reservoirs — New England Upland Paleozoic metamorphics (schist, gneiss, granite); surface water collection over granitic bedrock minimizes mineral dissolution; very soft water

Other Massachusetts Water Reports

Newtonville

≈ 0–60 mg/L

🟢 Soft

Newton

≈ 0–60 mg/L

🟢 Soft

Watertown

≈ 0–60 mg/L

🟢 Soft

Belmont

17.5 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 Waltham's water safe to drink?

Yes. Waltham'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 Waltham?

Waltham'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 Waltham compare to the USA average?

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