When residents report rusty or brown hot water, the building's central domestic hot water storage tanks are one of the first places to look.
How to narrow it down
Run hot and cold water separately into a white cup at the same tap, in a few different units.
If only the hot water is discoloured, in several units, the cause is likely in the hot water system. That means the storage tanks, the recirculation loop or the hot water piping.
If both hot and cold are discoloured across the building, start with the incoming water supply and the municipality.
If it's only one unit, it's likely local piping or a fixture.
Why tanks cause it
Large storage tanks are protected by an interior lining and sacrificial anodes. When the anodes are used up, corrosion starts at fittings and couplings. When the lining breaks down, the steel itself starts to rust. Sediment on the tank floor gets stirred up too. All of these show up as discoloured hot water.
What to do
Ask for an internal inspection of the tanks, not just a flush. A flush may clear the water for a while, but if the lining or anodes have failed, the problem comes back and keeps getting worse.
Caught early, this is usually fixed by replacing anodes, cleaning, and patching or relining the tank. Left alone, it's how tanks end up being replaced. Large tanks are an asset of the building, and replacing one is often a six-figure job, so it pays to deal with discoloured water early.
Who to call
Hydrastone inspects, maintains and relines large domestic hot water tanks across Canada. Call 416-902-8265 in Toronto, 778-996-8265 in Vancouver or 403-466-8645 in Calgary, or email info@hydrastone.com.
