Waltham Water Hardness & Quality Report (2026)
Water Hardness
3 grains per gallon
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
$0.14
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 Waltham, your appliances are currently losing 7% efficiency due to mineral buildup.
| Appliance | In Waltham | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.9 yrs | 8.5 yrs | -7% |
| Washing Machine | 11.7 yrs | 12 yrs | -3% |
| Water Heater | 13.5 yrs | 15 yrs | -10% |
Regional Water Comparison
How Waltham compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Waltham, Massachusetts | 52 mg/L | 6.7 ppt | 🟢 Soft | reservoir |
| Newton, Massachusetts | 103 mg/L | 10.3 ppt | 🟡 Moderately Hard | reservoir |
| Watertown, Massachusetts | 61.5 mg/L | 7.4 ppt | 🟡 Moderately Hard | reservoir |
| Belmont, Massachusetts | 123 mg/L | 11.6 ppt | 🟠 Hard | reservoir |
| Lexington, Massachusetts | 71 mg/L | 8 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Waltham compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Waltham | 52 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Waltham's Water Unique?
Local geology and source profile
Waltham, Massachusetts, 'the Watch City' in Middlesex County on the Charles River — a technology hub west of Boston (home of Brandeis University and the former Waltham Watch factory, now a technology campus) — draws its municipal water supply from the Hobbs Brook Reservoir (in the Hobbs Brook watershed in Lincoln and Waltham) and local surface water sources via the City of Waltham Water Division, treating Piedmont reservoir water for the Waltham area. Water hardness in Waltham measures 52 mg/L — classified as very soft.
Waltham's very soft supply reflects the eastern Massachusetts Piedmont crystalline watershed geology. The Hobbs Brook watershed in Lincoln and Waltham drains the Proterozoic Dedham Granite (the dominant Precambrian granitic basement of eastern Massachusetts — the calcium-poor Ayer Granodiorite and Dedham Granodiorite of the Milford–Dedham terrane) and the Paleozoic Cambridge Argillite and Brighton Melaphyre (mafic metavolcanic and argillite — calcium-poor). The crystalline and mafic volcanic rocks of the eastern Massachusetts Avalon terrane dissolve extremely slowly, producing naturally very soft reservoir water at 52 mg/L — identical to the broader eastern Massachusetts reservoir system chemistry (Portland ME: 52.5 mg/L from similar crystalline granite watershed geology).
With hardness at 52 mg/L, Waltham residents enjoy very soft water with essentially no scale challenges. City of Waltham Water Division consistently delivers water meeting all Massachusetts MassDEP and EPA Safe Drinking Water Act requirements.
Geology & Source: Reservoir supply from the Hobbs Brook Reservoir and Hardy Pond via the City of Waltham Water Division — the Massachusetts Piedmont Proterozoic–Paleozoic crystalline terrain (Middlesex County watershed — Hoppin Hill Granodiorite, Dedham Granite equivalents); very soft supply at 52 mg/L — consistent with eastern Massachusetts Piedmont crystalline reservoir supplies.