Cobourg Water Hardness & Quality Report (2026)
Water Hardness
~60–119 mg/L
Moderately Hardestimated · not lab-verified
Source
lake
pH Level
7.3
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
168.1 mg/L
Est. Daily Cost
$0.24
energy & soap waste
Source: Health Canada Water Quality · 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 Cobourg, your appliances are currently losing 12% efficiency due to mineral buildup.
| Appliance | In Cobourg | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.5 yrs | 8.5 yrs | -12% |
| Washing Machine | 10.6 yrs | 12 yrs | -12% |
| Water Heater | 13.2 yrs | 15 yrs | -12% |
Regional Water Comparison
How Cobourg compares to its nearest neighbours
| City | Hardness | Mineralization | Risk |
|---|---|---|---|
| ▶ Cobourg, Ontario | ≈ 60–119 mg/L | Medium | 🟡 Moderately Hard |
| Port Hope, Ontario | ≈ 120–179 mg/L | High | 🟠 Hard |
| Peterborough, Ontario | ≈ 60–120 mg/L | Medium | 🟡 Moderately Hard |
| Bowmanville, Ontario | ≈ 120–179 mg/L | High | 🟠 Hard |
| Quinte West, Ontario | ≈ 60–120 mg/L | Medium | 🟡 Moderately Hard |
National Benchmark
How Cobourg compares to the Canada average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Cobourg | ≈ 60–119 mg/L | 🟡 Low |
| Canada National Avg | 140 mg/L | 🟠 Moderate |
| Vancouver Top Rated | 3 mg/L | 🟢 None |
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What Makes Cobourg's Water Unique?
Local geology and source profile
The Corporation of the Town of Cobourg operates the Cobourg Drinking Water System, managed by Lakefront Utilities. Water is primarily drawn directly from Lake Ontario and treated at the Cobourg Water Treatment Plant. This system supplies drinking water to about 20,000 residents in Northumberland County, Ontario, Canada, serving residential, commercial, and industrial customers. The intake is directly from the lake, with no separate reservoirs or river sources mentioned. Standard filtration and disinfection processes are employed.
The Cobourg water supply is influenced by the limestone-rich geology of the Niagara Peninsula and central Ontario. Underlying the area are Paleozoic formations, including Ordovician Lindsay and Cobourg limestone formations. These carbonate rocks, along with potential blending from local aquifers within the Carbonate-Rock Aquifer System, contribute significant dissolved calcium and magnesium ions. This dissolution of calcite and dolomite in the bedrock results in a moderately hard water supply typical of the region.
At moderately hard levels, Cobourg's water can lead to noticeable scale buildup in appliances like hot water heaters and dishwashers, potentially reducing their efficiency and causing spots on glassware. Soap lathering may also be less effective, possibly leading to increased detergent use. Homeowners might consider periodic descaling of fixtures with vinegar or installing drain screens. Many residents find that a water softener is beneficial for mitigating these effects and prolonging the lifespan of their appliances. The Town of Cobourg's 2024 Annual Water Quality Report indicates full compliance with Ontario Regulation 170/03, with no adverse events and general testing showing no notable contaminants beyond the aesthetic hard water minerals.
Geology & Source: Lake Ontario surface water; limestone and dolomite bedrock of the Niagara Escarpment and Paleozoic formations produce hard water.
Other Ontario Water Reports
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