Marlborough Water Hardness & Quality Report (2026)
Water Hardness
7.1 grains per gallon
Source
reservoir
pH Level
8
neutral = 7.0
Lead
0.009 mg/L
✓ Below action level
TDS
325.8 mg/L
Est. Daily Cost
$0.33
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 Marlborough, your appliances are currently losing 16% efficiency due to mineral buildup.
| Appliance | In Marlborough | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.6 yrs | 8.5 yrs | -34% |
| Washing Machine | 9.1 yrs | 12 yrs | -24% |
| Water Heater | 10.7 yrs | 15 yrs | -29% |
Regional Water Comparison
How Marlborough compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Marlborough, Massachusetts | 122 mg/L | 11.6 ppt | 🟠 Hard | reservoir |
| Hudson, Massachusetts | 101.5 mg/L | 10.2 ppt | 🟡 Moderately Hard | reservoir |
| Ashland, Massachusetts | 81.5 mg/L | 8.8 ppt | 🟡 Moderately Hard | reservoir |
| Framingham Center, Massachusetts | 90 mg/L | 9.4 ppt | 🟡 Moderately Hard | reservoir |
| Sudbury, Massachusetts | 73.5 mg/L | 8.2 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Marlborough compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Marlborough | 122 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Marlborough's Water Unique?
Local geology and source profile
Marlborough, Massachusetts, in Middlesex County — a major central Middlesex County city in the Route 495 technology corridor, home of major technology and healthcare corporations (including Marlborough's significant medical device and semiconductor manufacturing base), a diverse Middlesex County community with significant Brazilian-American and Portuguese-American populations (Marlborough has one of the largest Brazilian-American communities in Massachusetts), and a revitalizing central Massachusetts city — draws its municipal water supply from Lake Williams and Lake Boon via the City of Marlborough Water Division. Water hardness in Marlborough measures 122 mg/L — classified as moderately hard.
Marlborough's moderate hardness reflects the central Middlesex County watershed's calcareous Nashoba Zone geology — notably harder than neighboring communities on the Precambrian gneiss terrain. The Lake Williams, Lake Boon, and Millham Reservoir watersheds at Marlborough drain: the Nashoba Zone (Ordovician–Cambrian calcareous Marlborough Formation — a distinctive calcareous meta-limestone and calcareous schist formation of the Nashoba Zone tectonic belt, named for Marlborough; significantly more calcareous than surrounding gneiss terrains); and Devonian Assabet Formation calcareous schist. The unusual calcareous Nashoba Zone Marlborough Formation produces the harder 122 mg/L compared to most central Massachusetts communities.
At 122 mg/L, Marlborough residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. City of Marlborough Water Division consistently delivers water meeting all Massachusetts MassDEP and EPA Safe Drinking Water Act requirements.
Geology & Source: Reservoir supply from the Lake Williams, Lake Boon, and Millham Reservoir watershed via the City of Marlborough Water Division — the Middlesex County central Massachusetts upland (Devonian calcareous-moderate Marlborough Formation calcareous schist and Ordovician Nashoba Zone calcareous metacarbonate of the central Massachusetts crystalline belt); moderately hard supply at 122 mg/L — reflecting the calcareous Nashoba Zone meta-limestone in the Marlborough watershed.