Markham Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
lake
pH Level
7.7
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
291 mg/L
Est. Daily Cost
$0.40
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 Markham, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Markham | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.8 yrs | 8.5 yrs | -20% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Markham compares to its nearest neighbours
| City | Hardness | Mineralization | Risk |
|---|---|---|---|
| ▶ Markham, Ontario | ≈ 120–179 mg/L | High | 🟠 Hard |
| Milliken, Ontario | ≈ 120–179 mg/L | High | 🟠 Hard |
| Agincourt North, Ontario | ≈ 60–120 mg/L | Medium | 🟡 Moderately Hard |
| Malvern, Ontario | ≈ 180+ mg/L | Very High | 🔴 Very Hard |
| Agincourt South-Malvern West, Ontario | ≈ 180+ mg/L | Very High | 🔴 Very Hard |
National Benchmark
How Markham compares to the Canada average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Markham | ≈ 120–179 mg/L | 🟠 Moderate |
| Canada National Avg | 140 mg/L | 🟠 Moderate |
| Vancouver Top Rated | 3 mg/L | 🟢 None |
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What Makes Markham's Water Unique?
Local geology and source profile
The City of Markham Water and Wastewater Division draws its municipal water supply entirely from Lake Ontario. This vast body of water serves as the primary source for numerous municipalities across the Greater Toronto Area. After collection, the water undergoes treatment at regional facilities before being distributed to residents throughout Markham and the surrounding York Region. Lake Ontario's watershed is a significant factor in the water's characteristics.
Geologically, Markham's water supply is influenced by Paleozoic carbonate bedrock. This includes extensive limestone and dolomite formations typical of southwestern Ontario. As water flows through these mineral-rich terrains and over tributaries, it naturally dissolves calcium and magnesium. This geological process is the reason Lake Ontario, despite being a surface water source, exhibits hard water qualities.
Homeowners in Markham often notice the effects of this hard water, with limescale buildup appearing in pipes and appliances. Water heaters can become less efficient, and spotting on dishes and glassware is a common complaint. Devices like dishwashers and washing machines may also see their lifespan shortened. While the water is safe to drink and meets all provincial quality standards, a whole-home water softener is frequently recommended to mitigate these issues and protect household plumbing and appliances.
Geology & Source: Lake Ontario watershed; Paleozoic limestone and dolomite bedrock produce hard water
Other Ontario Water Reports
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