Does hard water in Calgary damage a tankless water heater?

Calgary's water is genuinely hard, and tankless water heaters feel that more than tank units do. The City of Calgary reports hardness ranging from roughly 141 to 274 mg/L depending on which treatment plant supplies your neighbourhood and the time of year, and that calcium and magnesium can leave scale inside the heat exchanger.

What hard water actually does to a tankless unit

The heat exchanger in a tankless heater brings cold water to temperature almost instantly across a narrow coil or plate. Scale builds up on those surfaces, reducing heat transfer, forcing the burner to work harder, and eventually causing the unit to fault or crack the exchanger. You may notice the hot water taking longer to reach temperature, fluctuating output, or error codes appearing more often.

Regular descaling matters with Calgary water. The process circulates a descaling solution through the heat exchanger to dissolve scale. Check your unit's manual for the interval and for any maintenance the warranty requires.

A whole-house water softener reduces scale throughout the system, but the City of Calgary notes that salt-based softeners may not suit people on sodium-reduced diets and recommends researching the option before deciding. Some homeowners use a dedicated scale-inhibiting filter on the cold inlet to the heater as a middle ground; a plumber can size that for your flow rate.

Permits and certification in Calgary: a straight like-for-like tankless swap generally does not require a permit from the City of Calgary, but if the gas line upstream of the heater's shut-off valve changes, the venting changes, or the type of heater changes (for example, moving from a natural draft tank to a direct-vent tankless), a permit is required. Gas work on any heater must be done by an Alberta-certified gasfitter or a registered apprentice working under one; this is a compulsory certification trade under Alberta's Skilled Trades and Apprenticeship Education Act, and a homeowner in Calgary cannot pull a gas permit unless they hold that certification themselves.

What a fair quote for installation or replacement includes: a fixed price or clear hourly rate with a call-out fee, the specific unit by model number, any gas line or venting changes itemised separately, the permit if one is needed and who pulls it, removal and disposal of the old unit, and the warranty on both parts and labour in writing. If a gas line upgrade is needed, that adds roughly $400 to $1,500 to a tankless installation that otherwise runs about $2,200 to $5,000 supplied and installed in Calgary.

Before hiring, ask to see the gasfitter's Alberta trade certificate, confirm the contractor holds an Alberta prepaid contracting licence if you are paying any deposit before the work is complete, and request a WCB-Alberta clearance letter.

A useful question for any installer: what descaling interval do they recommend for your specific unit given Calgary's water hardness, and whether that service is included in any maintenance plan they offer.