Union Water Is Moderate — Here's What It Costs You Each Year

Why Is Union Water So Moderate?

Union water hardness is 6.9 grains per gallon (GPG), which is 118 parts per million (ppm). That puts it just under the USGS threshold for “hard” water, which starts at 6.9 GPG, so you’re sitting right on the line between moderate and hard. The reason it lands there has everything to do with where the water actually comes from, and that’s Lake Huron via the Elgin Area Primary Water Supply System, operated by Huron Elgin Water. This is surface water, plain and simple. It is not pulled from deep wells or limestone aquifers beneath your feet. Instead, it’s drawn from one of the Great Lakes, and that distinction matters more than most people realize.

Lake Huron’s water is relatively soft compared to groundwater because it hasn’t spent centuries soaking through calcium-and-magnesium-rich rock. Rain and snowmelt feed the lake directly, and that water runs off the Canadian Shield, which is dominated by ancient, hard, crystalline rocks like granite and gneiss. Those rocks are notoriously stingy with minerals. They don’t dissolve easily, so the water that reaches Lake Huron carries far less dissolved calcium and magnesium than water that filters through limestone or dolomite further south. That’s the whole story of why Union isn’t dealing with 15 or 20 GPG water like you’d find in parts of the American Midwest or southwestern Ontario. The lake simply doesn’t pick up the same mineral load.

That said, 6.9 GPG is not soft water either. Lake Huron’s open-water chemistry is influenced by the surrounding drainage basin, which includes some glacial till, clay, and scattered carbonate deposits left behind by retreating glaciers. As the water sits in the lake and moves through the intake and treatment process, it picks up a modest amount of dissolved solids. The calcium and magnesium detected in Union’s supply are the culprits behind that 118 ppm reading. It’s enough to leave a faint film on glassware and require a bit more soap in the washing machine, but it’s nowhere near the scale-building nightmare that plagues well-water users. You’re not imagining it if your water feels a touch different from bottled spring water, but you’re also not dealing with a mineral bomb. Fair enough.

How Union Compares to Nearby Cities

Because Union is served by the Elgin Area Primary Water Supply System, the water chemistry you get is largely shared by other communities drawing from that same Lake Huron-fed network. This is a regional system, not a single-town well field, so your neighbors to the east and west are drinking from the same source. That means the hardness you see at your tap, around 6.9 GPG, is very much in line with what other Huron Elgin Water customers receive. If you’ve ever filled a glass at a friend’s house in a nearby town on the same system and thought the water tasted familiar, you weren’t wrong. It’s the same lake water, treated and pumped through the same regional infrastructure.

The differences you might notice between Union and nearby communities usually come down to treatment adjustments or local storage, not a fundamentally different water source. Some towns in the region blend in groundwater during peak demand or have older distribution pipes that can add trace metals, but the baseline hardness stays consistent because the source is consistent. Compare that to communities further inland that rely on deep wells tapping into the Dundas Valley or other carbonate-rich aquifers, and you’ll see a stark contrast. Those groundwater systems routinely push past 10 or 12 GPG because the water has had centuries to dissolve limestone. Union’s Lake Huron supply sidesteps that entirely.

The practical difference shows up in your appliances and your detergent use. According to the Water Quality Association and Battelle Memorial Institute’s 2010 detergent study, soft water can cut laundry detergent use by up to 50% and dish soap by up to 70% compared to hard water. Union’s moderate 6.9 GPG sits in the middle ground, so you’ll use less soap than someone on a deep-well system but more than someone on truly soft lake water. Similarly, the Battelle Memorial Institute and WQRF’s 2009 research found that gas water heaters lose roughly 4% efficiency per 5 GPG of hardness, and the Department of Energy notes that just a quarter-inch of scale can cut water-heater efficiency by up to 40%. At 6.9 GPG, you’re not in the danger zone, but scale will still build over time. The WQA’s industry estimate, which scales with your actual hardness, points to higher energy and cleaning costs than a soft-water home would see, though the exact dollar figure depends on your household usage. Run the numbers through the calculator on this page to see what 6.9 GPG means for your specific situation.

How does Union stack up against the rest of Ontario? It's moderate at 6.9 GPG — Woodstock, Guelph, and Ingersoll sit nearby with different numbers. See the full hardest-water ranking for context.

See where Union 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.