A water heater is one of the most neglected major components of a home...until there is a leak causing water damage, no hot water, or brown hot water. While the general consensus is that a water heater will last in a home for about 10 years, with a bit of annual maintenance, it may easily last longer.
There are many variables that affect the life of a water heater, including the chemicals in your local water, but an annual flushing of the water heater can dramatically prolong its useful life and prevent the subsequent need for water damage removal. Follow the steps below to flush a water heater's tank. If your water heater is about 5+ years old and it has never been flushed, it is best at that point not to begin flushing it as the corrosion will probably have already begun and you may create more problems than you solve. However, you can DIY flushing your water heater by following the simple steps below or a plumber can perform this annual maintenance item for you. Instructions below are from The Family Handyman website.
(Photo of inside of corroded water heater tank)
2. Plumbers tape
4. Slip joint pliers
1. Pressure relief valve (if old one leaks)
Test the Valve
Test the pressure-relief valve located on the top or side of the water heater. This valve opens automatically if the pressure inside the tank gets too high. (Excess pressure can actually cause the tank to explode.) To test it, place a bucket below the discharge pipe on your water heater tank and gently lift the lever on the pressure-relief valve.
Replace the Valve (if Necessary)
If the valve doesn't release water when you lift the lever, replace the valve. Replacement is simple: Turn off the water, drain the tank, unscrew the discharge pipe and then unscrew the old valve. Wrap the threads of the new valve with sealant tape and screw it in. If your valve is several years old and has never been tested, it might leak after you test it. In that case, replace the valve.
Check Your Work
Close the shutoff valve on the cold water supply pipe that feeds the water heater. Then turn on the hot water at any faucet to release the pressure inside the heater's tank. Leave the faucet on until you finish your work. If you have an electric heater, turn off the power at the main panel. With a gas heater, turn the gas control dial to "off."
How to Adjust Water Heater Temperature
Drain the tank to flush out sediments that have settled to the bottom of the tank. Sediment buildup shortens the life of your water heater and adds to your energy bill by reducing its efficiency. Draining two or three gallons of water is usually enough to flush out sediments, but always let the water flow until you no longer see particles in the bucket. Open the drain valve slowly and let the water run until it's clear and free of sediments.
Don't worry about any gurgling or groaning noises coming from the heater. That sound is just air entering the system as water drains out. If the drain valve won't close tightly when you're done, drain the tank completely, unscrew the old valve and screw in a new one. To restart the water heater, open the shutoff valve and let the hot water run at any faucet to purge air from the system. Then turn on the power or relight the pilot.
Set your water heater's dial to 120 degrees F. If the dial doesn't have numbers, check the water temperature with a cooking thermometer. Higher temperatures increase sediment buildup and the risk of scalding injuries.