What is an anode rod? This rod in its proper term is a sacrificial anode. It allows water and electrostatic charges to eat away the anode material instead of the tank. Anode rods are made of several different materials.

The most common material is magnesium. Some rods last the life of the tank and others disintegrate in less than two years. This is purely based on the water. The other type of rod is made from aluminum. Aluminum is used in areas with mainly well water and a bad smell like rotten eggs has come from the hot water tank when using a magnesium rod. The aluminum rod is a special order from the manufacture.

Replacing the Anode Rod  

The rod can be found in one of two places, under a large 1 1/16” nut on the top of the tank is the most common place. The other location would be on the nipple of the outlet side of the hot water plumbing and require cutting and soldering of the copper pipe. Once again it depends on the manufacture of the tank.

To replace the rod under the nut, first turn off the water supply to the tank. If the tank is a power vent and is plugged in, unplug it. If the tank is a standard tank with a metal chimney, turn the temperature down to vacation. If you find the shut off does not completely turn off the water supply, then turn off the main water supply to the house. Attach a hose to the drain valve at the bottom of the water heater with the other end being placed in a floor drain.

Before opening the drain valve on the tank, open a hot water tap only at any sink in the house and relieve the pressure on the hot water tank. If you have single taps, swing the handle all the way to the hot water side and allow the hot water pressure to be relieved. Once the water stops coming out with any pressure, close up the tap so the system is isolated. This is called a hydraulic lock. Draining the entire house is not required. Be sure to tell others in the house not to use any water while you are doing your repair or a flood could be the result.

With the tank pressure relieved, open the drain valve located on the bottom of the water heater. This will prevent water from gushing from residual pressure buildup,  upward from the anode hole when the anode is removed.

You will require a Johnson bar and an appropriate socket to fit the large nut on the top of the water heater, usually 1 1/16” or 1 1/8” socket. The nut will be very tight so be prepared to support the tank when loosening. Once the nut is loose it should be able to be unscrewed by hand. Pull the rod straight up and you have now removed the rod.

If you find the rod is in good condition, you can reuse it. Place either pipe dope or thread tape on the threads of the new or existing anode rod and reinstall. Over tightening is not required as it is only water pressure of usually less than 80 psi.  The nut requires less torque than a wheel nut on a car.

Once the anode has been replaced, close the drain valve at the bottom of the tank and open the water shut off and main if this had been closed. Go to the sink at the highest point in the house and open the hot water tap to bleed and air in the system. You are now done.

It is also suggestible to flush the tank after this process. Please see my video for help.