The basics
Peel Region's water is moderately hard. As it heats, dissolved minerals drop out and settle in the bottom of the tank as a layer of scale and grit. Over time that crust blankets the water from the burner or lower element, so the heater runs longer to reach the same temperature. It also makes the popping and rumbling noise many owners hear, and it can clog the drain valve.
Flushing removes the loose sediment before it hardens. It will not reverse years of neglect, and it will not fix a leaking tank, but on a heater that is still sound it is the most useful maintenance you can do.
Before starting, check two things. If your tank is a rental, read your agreement; some providers prefer to do maintenance themselves. And if the heater is more than about twelve years old and has never been flushed, call us first, because opening a long-neglected drain valve sometimes means it will not close again.
Step by step
- Turn off the heat. Gas tank: dial to pilot or vacation. Electric tank: breaker off.
- Close the cold supply. The valve is on the cold line at the top of the tank.
- Let it cool. Wait a few hours, or overnight, so the water is not scalding.
- Attach a hose. Attach a hose to the spigot at the foot of the tank and lead it to the nearest floor drain or sump pit.
- Open a hot tap upstairs. Air rushing in helps the tank empty quickly.
- Crack the drain valve open. Let the tank empty. Watch the water at the hose end for grit.
- Stir it up. With the drain open, briefly open the cold supply to churn the bottom, then close it again. Repeat until the water runs clear.
- Refill. Close the drain valve, remove the hose, reopen the cold supply, and let the upstairs hot tap run until it flows smooth and quiet.
- Restore heat. Relight or return the gas control to its setting, or restore the breaker only after the tank has refilled.
While you are there
Look at the rating plate for the manufacture date; our guide to water heater age explains the codes. Check the temperature-pressure relief valve's discharge pipe for drips, and look for rust at the base and fittings.
Time to bring in the shop
Call if the drain valve will not open or will not shut fully, if the water never runs clear, or if you see moisture under the tank. Those are signs the tank needs repair or, for older units, replacement. Tankless heaters need a different process, a vinegar or descaler circulation, covered on our tankless descaling page.
Asked at the shop counter
How regularly should the tank be drained?
Once a year suits most Brampton homes. Homes with a softener can stretch it a little longer.
Why is my tank still noisy after flushing?
Hardened scale may remain stuck to the bottom. It may quieten over several flushes, or it may be a sign of age.
Can flushing cause a leak?
Old drain valves sometimes drip after being opened. A replacement valve is a quick fix.
Questions about this job? Call (365) 413-9125 and talk to a plumber.