Cobourg Water Hardness & Quality Report (2026)
Water Hardness
Source
lake
pH Level
7.8
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
414.4 mg/L
Est. Daily Cost
$0.49
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 24% efficiency due to mineral buildup.
| Appliance | In Cobourg | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 3.5 yrs | 8.5 yrs | -59% |
| Washing Machine | 6.8 yrs | 12 yrs | -43% |
| Water Heater | 8.3 yrs | 15 yrs | -45% |
Regional Water Comparison
How Cobourg compares to its nearest neighbours
| City | Hardness | Mineralization | Risk |
|---|---|---|---|
| ▶ Cobourg, Ontario | 183.5 mg/L | High | 🔴 Very Hard |
| Port Hope, Ontario | 258 mg/L | Very High | 🔴 Very Hard |
| Peterborough, Ontario | 95 mg/L | Medium | 🟡 Moderately Hard |
| Bowmanville, Ontario | 201 mg/L | Very High | 🔴 Very Hard |
| Quinte West, Ontario | 166 mg/L | High | 🟠 Hard |
National Benchmark
How Cobourg compares to the Canada average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Cobourg | 183.5 mg/L | 🔴 High |
| Canada National Avg | 141 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
Cobourg's drinking water is managed by the Town of Cobourg, drawing from Lake Ontario via the Cobourg water treatment plant on the north Lake Ontario shoreline — Cobourg is a historic Northumberland County town known for its Victoria Hall civic building, one of Ontario's most beautiful Victorian-era public buildings, and as a bedroom community for Oshawa and Toronto GTA commuters via the GO train. Water undergoes coagulation, sedimentation, filtration, UV disinfection, and chloramination, meeting all Guidelines for Canadian Drinking Water Quality (GCDWQ) requirements. Hardness measures 183.5 mg/L (10.7 gpg) — classified as very hard by Health Canada, reflecting eastern Lake Ontario's supply character in the Northumberland County corridor.
Cobourg's 183.5 mg/L is on the softer end of the eastern Lake Ontario supply band — softer than the Durham Region supply (Whitby 213 mg/L, Uxbridge 210.5 mg/L) and the central Toronto supply (230–240 mg/L). Lake Ontario at the Cobourg intake (easternmost of the north shore communities in the dataset) shows the characteristic slight hardness decrease moving east along the north shore as the Lake Ontario mixing pattern produces somewhat less mineralised water in the eastern basin compared to the western end near Toronto and Niagara. The Ordovician limestone bedrock of the Northumberland County shoreline contributes moderate dissolved calcium to the lake intake.
At 183.5 mg/L, Cobourg residents face regular scale challenges — monthly to bimonthly kettle descaling is typical. Hot water tanks benefit from periodic inspection and flushing. The Town of Cobourg provides water quality information at cobourg.ca. Cobourg's popular heritage downtown and retirement community character bring many residents from Toronto who will find the supply slightly softer than their previous GTA address, though still well within the very hard category. Health Canada lead precautionary guidance applies to older pre-1940 properties in the historic Victoria Hall–era downtown core.
Geology & Source: Supplied by Municipality of Port Hope area or Town of Cobourg from Lake Ontario — the Northumberland County Lake Ontario north shore supply produces very hard water at 183.5 mg/L (10.7 gpg), reflecting eastern Lake Ontario's moderate-hard supply band.