What causes white flakes in my hot water?

White flakes in your hot water are almost always caused by mineral scale breaking loose from the inside of your water heater — specifically calcium and magnesium deposits that build up over time as hard water is heated.

Ottawa has moderately hard water, and when water is heated repeatedly, those dissolved minerals precipitate out and coat the interior of your tank. Over years, this scale layer thickens, eventually cracking and flaking off into your hot water supply. You'll notice it most at faucets and showerheads, and sometimes as a gritty feeling on your skin.

What the flakes tell you about your water heater's condition matters here. A small amount of occasional flaking is normal in a tank that's 5+ years old. Heavy, consistent flaking — especially if accompanied by rumbling or popping sounds from the tank — means significant scale buildup has occurred. That sediment layer forces your heater to work harder, raises your energy bills, and shortens the unit's lifespan. Most water heaters in Ottawa last 10-12 years, but heavy scale can cut that down considerably.

If your tank is under 8 years old, a professional flush and descale can often resolve the problem and buy you several more years of service. A licensed plumber will drain the tank, flush out the sediment, and inspect the anode rod — a sacrificial metal rod that protects the tank from corrosion and should be replaced every 3-5 years. Neglecting the anode rod is the #1 reason water heaters fail prematurely.

If your tank is 10+ years old, flaking is often a sign it's nearing end of life. At that point, investing $200-$400 in a flush may not make sense compared to a full replacement ($1,500-$2,500 installed in Ottawa for a standard tank unit).

Going forward, annual flushing is the best prevention — it takes about an hour and dramatically reduces scale buildup. Installing a whole-home water softener is another option worth considering if hard water is a recurring issue throughout your home.

If you're seeing heavy flaking or your unit is aging, Ottawa Pro Plumbing can inspect your water heater and give you an honest assessment of whether to flush or replace. Feel free to request a free estimate.