Water hardness in Markham
Markham, Ontario tap water is moderately hard, drawn from lake ontario via york region supply network (purchased from city of toronto and region of peel). Here is what it means at home, and the source.
What this means at home
Some kettle and showerhead scale over time, but most homes get by without a softener.
Markham purchases treated Lake Ontario water through York Region, which sources it from the City of Toronto and Peel Region. The city reports a single hardness figure on its tap-water quality page.
You likely do not need a softener. A quick test kit confirms it for your own tap.
New to this? Read hard water, explained, including whether it is safe to drink and how to test your tap.
The number, in real terms
At 123 mg/L (7.2 grains per gallon), a four-person Markham household puts only about 2,158 grains of hardness a day through its plumbing (industry sizing convention: about 300 US gallons a day). That is a light enough load that most homes skip the softener and just descale the kettle now and then.
Scale ceiling: every 1,000 litres heated can leave at most 123 grams of scale, because that is the total mineral carried at 123 mg/L. Real kettles and water heaters precipitate a fraction of that, but the ceiling scales with the number: Markham's moderately hard water leaves little behind.
How this is calculated: grains per gallon = mg/L divided by 17.1; daily grain load = gpg x 300 US gallons (the softener trade sizes in US gallons, four-person household); regeneration interval = 32,000 grains divided by the daily load; scale ceiling = mg/L carried per 1,000 L. The input figure is City of Markham's own published number, checked 2026-07-03. Full method on the methodology page.
Markham water hardness questions
How hard is the water in Markham?
Markham's tap water is moderately hard, about 123 mg/L as calcium carbonate (7.2 grains per gallon), drawn from lake ontario via york region supply network (purchased from city of toronto and region of peel). Figure from City of Markham, last checked 2026-07-03.
Do I need a water softener in Markham?
Probably not. Markham water is moderately hard, so most homes get by without one. A simple test kit settles it if you are unsure.
How does Markham compare with nearby towns?
Closest verified figures: Fort Erie at 123 mg/L mg/L, Lakeshore at 89.90 to 214.80 mg/L as CaCO3 (average 122.62) mg/L, Niagara Falls at 123 mg/L mg/L. Markham sits at 123 mg/L, all measured as calcium carbonate.
Source
Source: City of Markham, last checked 2026-07-03. Hardness varies by neighbourhood, season, and which well or plant serves your street, especially on groundwater systems. These are the municipal published figures as of the verified date, good for planning, not a substitute for a home test or your utility's current report.
Compare nearby verified figures: Fort Erie (123 mg/L mg/L), Lakeshore (89.90 to 214.80 mg/L as CaCO3 (average 122.62) mg/L), Niagara Falls (123 mg/L mg/L). Or see every municipality.