Markham Water Hardness & Quality Report (2026)
Water Hardness
Source
lake
pH Level
7.7
neutral = 7.0
Lead
0.001 mg/L
✓ Below action level
TDS
250 mg/L
Est. Daily Cost
$0.35
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 17% efficiency due to mineral buildup.
| Appliance | In Markham | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 5.3 yrs | 8.5 yrs | -38% |
| Washing Machine | 8.8 yrs | 12 yrs | -27% |
| Water Heater | 10.4 yrs | 15 yrs | -31% |
Regional Water Comparison
How Markham compares to its nearest neighbours
| City | Hardness | Mineralization | Risk |
|---|---|---|---|
| ▶ Markham, Ontario | 130 mg/L | High | 🟠 Hard |
| Toronto, Ontario | 124 mg/L | High | 🟠 Hard |
| Vaughan, Ontario | 130 mg/L | High | 🟠 Hard |
| Etobicoke, Ontario | 190 mg/L | Very High | 🔴 Very Hard |
| Mississauga, Ontario | 130 mg/L | High | 🟠 Hard |
National Benchmark
How Markham compares to the Canada average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Markham | 130 mg/L | 🟠 Moderate |
| Canada National Avg | 104 mg/L | 🟡 Low |
| Vancouver Top Rated | 3 mg/L | 🟢 None |
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What Makes Markham's Water Unique?
Local geology and source profile
Markham receives its drinking water through York Region, which purchases treated water from Lake Ontario via interconnection agreements with the Region of Durham (drawing from Lake Ontario at Ajax) and supplementary Toronto Water supply. York Region distributes this water through its own transmission and storage network serving Markham, Richmond Hill, Vaughan, and surrounding municipalities. All supply meets the Guidelines for Canadian Drinking Water Quality (GCDWQ), and hardness at the tap is 130 mg/L (7.6 gpg) — moderately hard by Health Canada standards.
Markham's water originates in Lake Ontario's eastern basin, which receives inflow from the Trent and Cataraqui watersheds draining Ordovician and Silurian carbonate formations in the Ontario Shield transition zone. By the time Lake Ontario water is treated and transmitted north to York Region, it carries a consistent dissolved mineral load representative of the southern Ontario limestone and dolomite geology. Hardness levels in York Region are consistent year-round, with minimal seasonal fluctuation.
Markham residents notice moderate limescale deposits on kettle elements, tap aerators, and showerheads — regular descaling every six to eight weeks is advisable. Hot water tanks in Markham homes accumulate scale on heating elements at a moderate rate; York Region recommends periodic inspection and flushing. A whole-home water softener significantly reduces cleaning time and extends appliance lifespan for households with high water usage.
Geology & Source: Supplied by York Region from Lake Ontario via transmission mains from the Region of Durham and Toronto Water networks — Great Lakes Silurian dolomite basin chemistry delivers water at 130 mg/L (7.6 gpg).