What causes hard water and how do I fix it?

Hard water is caused by dissolved minerals — primarily calcium and magnesium — that accumulate as water passes through limestone and rock formations before reaching your tap. In Ottawa, the water supply comes from the Ottawa River, and while the city treats it, the natural mineral content means many Ottawa homes experience moderate hard water.

Why It Happens

As groundwater or surface water moves through geological deposits, it picks up calcium carbonate and magnesium. The "hardness" is measured in grains per gallon (GPG) or milligrams per litre (mg/L). Ottawa's municipal water typically falls in the moderately hard range, which is enough to cause noticeable buildup over time without being extreme.

What It Does to Your Plumbing

Hard water leaves limescale deposits inside pipes, water heaters, and fixtures. Over years, this buildup can reduce water flow, cut water heater efficiency by 20-30%, and shorten appliance lifespans significantly. You'll notice it as white crusty buildup around faucets, spots on dishes, and soap that doesn't lather well.

Your Fix Options

The most effective long-term solution is a whole-home water softener, which uses an ion exchange process to replace calcium and magnesium with sodium. These systems typically cost $1,500 - $3,500 installed in the Ottawa market. A more modern alternative is a salt-free water conditioner, which doesn't remove minerals but prevents them from bonding to surfaces — lower maintenance, but less aggressive on existing buildup.

For targeted fixes, descaling filters on specific fixtures or a point-of-use reverse osmosis system under the kitchen sink ($400 - $800 installed) can address drinking water quality without treating the whole home.

Protecting Your Plumbing Long-Term

If you've had hard water for years without treatment, it's worth having a plumber inspect your water heater — limescale buildup is a leading cause of premature water heater failure in Ottawa homes. Flushing your tank annually and checking for sediment can add years to its life.

A licensed plumber can also test your water hardness and recommend the right system size for your home's water usage. If you'd like to discuss your specific situation, Ottawa Pro Plumbing offers free consultations and can assess whether your existing plumbing has been affected by mineral buildup.