How to Replace an Anode Rod in a Water Heater and Extend Its Life by Years

Depending on the type of hot water heater you have, you’ll either have to drain it partially or completely before you can remove the anode rod. Since you’ll be draining the water heater to remove the rod, you can kill two birds with one stone by using this opportunity to also flush and clean the water heater.

First, shut the valve on the cold water line that’s responsible for filling your water tank. Next, open a hot water faucet somewhere in your home to relieve pressure on the tank. Water won’t drain from the water heater unless a faucet is open. The closer the faucet is to the heater, the faster it will drain. 

Next, you’ll want to connect a garden hose to the drain valve at the bottom of the tank and run the end of the hose to your basement drain or a location outside your home. Open the drain valve and drain about two gallons of water if the anode rod is located on the top of the tank. If it’s on the side, you’ll need to drain it entirely.

Look at the top of the tank for a hexagonal-shaped plastic cap, which marks the location of the anode rod. If you can’t locate it on top of the water heater, check the sides. Once you find it, remove the plastic cap to expose the anode rod head. There may be insulation under the plastic cap. If so, use a screwdriver to dig it out, so you can get to the rod. 

Insert a 1/16-inch socket over the anode rod head, then use a breaker bar to rotate it counter clockwise. Since anode rods corrode over time, they’re notoriously difficult to loosen from water heaters. While you can attempt to use a standard socket wrench, you likely won’t be able to generate enough torque to break the anode rod’s seal. Use the breaker bar instead. Its longer length will give you the power you need to free the rod. 

If you have another set of hands available, have your helper hold on to the tank to prevent it from moving while you’re attempting to remove the rod. If the rod is especially stubborn, try tightening it slightly to break the threads loose before loosening it. Never use penetrating fluid on an anode rod as it can seep into the tank, contaminating your water supply. 

Expect some water to leak out as you're removing the anode rod, so have a rag nearby to wipe it up.

Lift the anode rod out of the hot water tank. If you have limited clearance around your hot water heater, you may need to bend the anode rod to get it out. Be careful with this step, as the anode rod may still be hot. 

Once the rod is out, you’ll likely notice deterioration on the rod, which is normal wear and tear. If the anode rod has so much sediment attached to it that you can’t remove it from the tank, then it means it’s still working. Tighten the rod back in place and check it again in a year.

Wrap the threads on the new rod with Teflon™ tape. You’ll want to make at least six revolutions around the rod’s threads to ensure there’s a water-tight seal once you install it. Don’t skimp on the tape or you could end up with a leak, forcing you to remove the rod and re-wrap it.

Slide the anode rod back into the tank. Thread it a few turns by hand, then use the socket and breaker bar to tighten it another half turn. In some cases, you may not have enough clearance above your water heater to install the new rod. In that case, use a flexible replacement rod. 

Make sure the hot water tank drain is closed and turn the cold water supply back on. Open the hot water faucet you used to drain the tank and allow water to flow through it until all the air has been removed. The faucet will make hissing and sputtering noises as air escapes from the line. Check for any leaks around the anode rod then turn on the power and gas. If you have a gas water heater, check with the manufacturer’s instructions to relight its pilot light.