Clorox bleach can be introduced to a houses' water system to disinfect the plumbing and hot-water heater. Do this if you notice a bad smell or taste coming from your water. This process is done by diluting bleach in water and siphoning it through a faucet into the entire system, where it ultimately ends up draining out of the water heater. Choose a plain bleach that is unscented and does not contain any added chemicals.
Empty the water heater by attaching a hose to the drain on the bottom and turning the valve directly above the spout. This will allow the water to flow out into a bucket.
Turn the water heater off, or change it to the lowest setting possible if it can't be turned off.
Turn off the cold-water valve on the top of the water heater.
Mix the appropriate amount of bleach with 2 gallons of water to dilute it. Use the information below: 40-gallon water heater: 3 1/4 cups bleach 50-gallon water heater: 4 cups bleach 80-gallon water heater: 6 cups bleach 120-gallon water heater: 8 3/4 bleach
Attach a second piece of hose to a nearby faucet.
Place the second end of the hose connected to the water heater drain into the bucket of bleach solution.
Open the water heater drain, and turn on the faucet to which the second hose is connected at the same time. This will create a vacuum effect, and the piping will suck up the bleach solution. It will then travel through the entire plumbing system and into the hot-water tank. When all of the bleach solution is in the system, close the water heater drain so it does not start draining out.
Reopen the cold-water valve on the water heater, and open all of faucets in the house to get the water flowing. Once water starts coming out, close the valves.
Wait 12 hours, then open the drain on the water heater to allow the water to escape.