The how and why of replacing a geyser’s sacrificial anode

Replacing a geyser’s sacrificial anode can prevent a burst geyser and a flooded home.

Most of us never think about our geyser until it stops working, leaks or bursts. (Or when the electricity bill arrives and you realise you should turn down the geyser to save money!). Instead, we should actually be inspecting our geyser every now and again, including checking the sacrificial anode and replacing it if necessary.

So what is a ‘sacrificial anode’, what does it do and why does it need to be replaced?

The sacrificial anode is an essential component of your geyser – a long metal rod usually made of a soft metal such as magnesium or aluminium. It extends into the tank’s interior and attracts – through an electrochemical process – particles of iron, limescale and other minerals present in the water. Instead of these minerals corroding the inside of the tank, the rod is designed to corrode and be ‘sacrificed’, hence the name ‘sacrificial anode’. If the anode was not present. The inside of the tank would corrode and potentially lead to a burst geyser and all the associated problems. Anodes should be checked every year or second year – the rate at which they corrode depends on the mineral content of your water.

Inspecting and changing the anode is something you can do so easily yourself. Start by switching off the geyser at the DB board and draining it to below half via the drain port. Once that is done, simply unscrew and remove the anode using a socket, usually a number 30. Have a look at the anode – if it is visibly pitted and corroded, it has done its job and it’s time for a new one. Installing a new one is as simple as screwing in the replacement and seating the O-ring in place – just make sure that you have the correct size anode and O-ring.

And there you have it – replacing an anode is a simple job you can do for yourself in 10 minutes and it is way cheaper and easier than replacing a whole geyser. Builders have sacrificial anodes, O-rings and geysers in stock, both in-store and online.