Chances are you have a hot water heater at home. The YouTube channel, The Home Depot, explains how periodically flushing it out will extend the life of the heater, and how to do it without calling water heater services.
First, determine whether your heater is powered by electricity or gas.
If electric, shut off the power to the heater. If powered by gas, then find your gas valve and turn it off. Also, find the water valve and turn that off as well.
Next, you’ll need to release some excess pressure from the tank. Make sure you have a bucket handy to collect the water. Once that is in place, flip the release valve to release the water. Use a pipe wrench to take the valve off the tank and check it for any degradation. If you want to give it a better water-tight seal, get some Teflon tape and wrap it around the threads clockwise.
To flush out the tank completely, attach a garden hose to the drain valve and release the water outside your home. Then turn the water valve back on to refill the tank. Afterwards, turn on the power and relight the pilot.