Water Heater Cleaning Chemicals

Hydrogen Peroxide

• Both hydrogen peroxide and bleach serve as effective chemicals for eliminating odor-causing sulfur bacteria from the water heater. These bacteria give off a distinctive smell, similar to rotten eggs, when they settle into your water heater. To kill these bacteria, try pouring 2 to 3 pints of hydrogen peroxide into the top of the water heater after removing the hex nut and cathodic anode at the top of the unit. Let it sit in tank for a few hours, then drain the tank and allow it to refill with fresh water. Drain once more to rinse, then refill it and use normally.

Chlorine Bleach

• If you have a sulfur bacteria problem and hydrogen peroxide doesn't eliminate the problem, use chlorine bleach to clean both the water heater and all attached fixtures. You'll need to dilute chlorine bleach and place it in a bucket under one of your sinks. The University of Nevada Cooperative Extension recommends using between 3 1/4 and 8 3/4 cups of bleach depending on the size of your water heater. Attach a hose to the faucet and let the other end of the hose extend into the bucket. By turning on the sink and opening the drain on your water heater at the same time, you can siphon the bleach through your entire plumbing system. After 12 hours, drain the system, refill the tank with clean water and run hot water at each sink until the smell of bleach disappears.

Vinegar

• A popping sound in your water heater or a slowly dwindling supply of hot water may indicate a buildup of limescale in your unit. Vinegar serves as a mild chemical for cleaning limescale and restoring the function of your hot water heater. Start by turning electric water heaters off and switching gas units to the "Pilot" setting. Turn off the water supply to the unit and drain the tank using the drain valve at the bottom. If you have an electric water heater, take the heating elements out and place them in a pan filled with apple cider vinegar to remove limescale. Pour 1 gallon of apple cider vinegar into your tank and allow it to sit for at least six hours before draining the tank, then replace electric heating elements and refill the tank.

Lye and Lime Removers

• If vinegar isn't tough enough to tackle the mineral salts in your water heater, you may need to turn to harsh chemicals like lye or commercial lime removers. When using these caustic products, use caution to protect your skin and eyes, and work in a ventilated area. After turning off the water and draining the tank, pour 1 cup of liquid lye into your tank, then add 3 to 4 gallons of cold water. Allow the lye to sit in the tank for three hours, then add a quart of household vinegar to the tank. Turn the water supply on and wait for it to fill about one-third of the tank, then drain your water heater. Flush twice more with vinegar to ensure all lye has been removed. If you choose a commercial lime remover instead of lye, follow the instructions on the package to determine how much to use and how to flush it from the system when you are done.