Newmarket Water Is Hard — Here's What It Costs You Each Year

Why Is Newmarket Water So Hard?

Newmarket doesn’t drill its own wells or pull from a local creek. The taps here are fed by York Region’s municipal system, which blends surface water from Lake Ontario and Lake Simcoe with groundwater from the regional aquifers. That mix is the whole story behind your 8.2 GPG hardness, and it’s worth understanding why.

Lake Ontario and Lake Simcoe sit in the Great Lakes basin, which is essentially a giant limestone bowl. The bedrock under this part of Ontario is dominated by Paleozoic-era dolomite and limestone, both of which are carbonate rocks. Rain and snowmelt pick up carbon dioxide as they fall, forming weak carbonic acid. That mildly acidic water seeps through the soil and into the rock, and it slowly dissolves the calcium and magnesium carbonates out of the limestone and dolomite. The result is water that’s naturally loaded with dissolved hardness minerals before it ever reaches a treatment plant.

The groundwater component in York Region’s supply tells the same story, only slower. Aquifers in this area are typically housed in glacial till and fractured limestone, and the water that’s been sitting in contact with that rock for years has had plenty of time to dissolve minerals. Surface water from the lakes tends to run a bit softer than deep groundwater, but when the two are blended, you land right in the middle. At 8.2 GPG, you’re sitting just above the 7 GPG threshold that the USGS classifies as “hard” and a few notches below the 10.5 GPG line where water officially becomes “very hard.” That’s not an extreme reading, but it’s firmly in the range where scale buildup and soap scum become everyday realities.

The iron in the water, which York Region has detected, is a separate issue from hardness, but it often travels with it. Iron dissolves out of the same bedrock and glacial deposits, and while it’s not regulated by the EPA as a health hazard, it can stain fixtures and laundry. The sodium detected is typically a byproduct of the water treatment process rather than geology, but both are worth knowing about if you’re considering treatment equipment.

How Newmarket Compares to Nearby Cities

The honest answer here is that Newmarket’s water is essentially the same water that most of York Region drinks. Aurora, Richmond Hill, Vaughan, and Markham all draw from the same York Region municipal system, which means they’re pulling from the same blend of Lake Ontario, Lake Simcoe, and groundwater sources. If your neighbour in Aurora has scale on their kettle, you’re likely dealing with the same situation in Newmarket.

That said, the blend isn’t perfectly uniform across the region. York Region operates multiple treatment plants and well fields, and the ratio of surface water to groundwater can shift depending on the season, demand, and which plant is serving which area. A home in northern Newmarket might be getting a higher proportion of groundwater from local wells, while a home in southern Markham could be pulling more from the lake-based treatment plants. Groundwater tends to run harder than surface water, so it’s plausible that two homes twenty minutes apart could see a difference of a few grains per gallon. But without testing each tap, nobody can say for sure which direction that difference goes.

The bigger point is this: if you’re comparing Newmarket to a city like Toronto, which draws exclusively from Lake Ontario, you might notice a difference. Lake Ontario water is typically softer than the blended York Region supply because it’s all surface water with less contact time with limestone. But comparing Newmarket to its immediate neighbours in York Region, you’re looking at the same source, the same geology, and the same general hardness range. The differences are minor, and they’re more likely to reflect which treatment plant you’re on than any fundamental difference in the water itself.

One thing that does vary is the age and condition of the pipes between the treatment plant and your home. Older neighbourhoods with galvanized or iron service lines can pick up additional iron and sediment, which can make the water seem harder or more staining than it actually is at the source. That’s a local condition, not a regional one, and it’s worth keeping in mind if your water seems noticeably worse than a friend’s across town.

How does Newmarket stack up against the rest of Ontario? It's hard at 8.2 GPG — Woodstock, Guelph, and Ingersoll sit nearby with different numbers. See the full hardest-water ranking for context.

See where Newmarket sits on the Ontario water hardness map →

Want the broader explainer on what hardness actually is and how it behaves? Read hard water vs. soft water, explained.