A Crash Course In Social Media

How To Replace The Magnesium Anode Rod In Your Water Heater

by Kyle Marshall

You can extend the life of your water heater simply by replacing the magnesium anode rod before it fails, slowing down corrosion in the tank.

The anode rod works by attracting corrosive elements that are present in the water, thus protecting the lining of the tank. Over time the rod becomes corroded and can't perform its role efficiently, meaning that the tank rusts and begins to leak. If you replace the anode rod in your water heater every five years or so, you can actually double the life of your tank.

You can buy replacement anode rods from most good DIY stores. Here's how to replace a magnesium anode rod in your hot water tank.

Locate the anode rod

You can usually see the anode rod on the top of the water heater, presenting as a hexagonal head. If this is not present, the rod could be under the metal top, and you should check your owner's manual to determine its location.

How to do it

First of all, close the shut-off valve and turn on a hot water tap to depressurise the tank. Switch off all power to the heater. Open the drain valve at the bottom of the tank and remove a few buckets of water. Orange water can mean that there is some corrosion in the tank or associated pipework, but is not generally a cause for immediate concern.  However, if you discover flakes of metal or rust in the water, the tank may need replacement.  

Loosen the rod, using a suitably sized spanner. Give the rod a good spray with light oil or WD40 and allow it to penetrate, before trying to loosen the rod again. If the anode rod is badly corroded, you may need to use an air compressor to loosen it, before it can be removed. Unscrew the rod and lift it out.

If your tank is located in your roof space and has limited clearance from the roof, bend the rod to get it out, and choose a flexible, segmented design of anode rod as a replacement.  

Smear the threads of the new anode rod with pipe thread sealant before you install it. This will make it easier to screw the rod into position and will also prevent corrosion and leakage.  

Then insert the new rod and tighten up the hex top, using your spanner.  Finally, turn the power back on. Switch on the water and bleed the system to get rid of trapped air.