While water filters are generally quite light when it comes to maintenance, most domestic water filters work by means of a salt cartridge which draws out and captures contaminants in the water, removing it from the water supply and leaving you with clean drinking water. In these systems, it’s the cartridge itself that arguably does most of the work and that means it’s the most important part of the system.

These cartridge-based water filters are quite comfortably the most affordable and popular systems on the market, but the cartridge will need to be changed semi-regularly as it gets full of material. Of course, how long your cartridge lasts will depend largely on how often you use it and the hardness of the water in your area. Generally speaking, you should aim to replace your water filter cartridge every 3 – 6 months, though there are always going to be exceptions.

Either way, eventually you are going to have to swap out your cartridge with a replacement that’s compatible with your system. Thankfully, replacement is remarkably straightforward but to ensure you are completely confident with replacing your own cartridges, we’ve put together a foolproof 6-step guide.

Step 1 – Switch off your water supply to the system at the stopcock.

If you don’t know where your stopcock is, try checking in your kitchen underneath the sink and follow your pipes. Once you’ve turned off the water, open the filter tap and release any pressure that might have built up.

Step 2 – Using a spanner, unscrew the housing bowl from your filter but be wary as it will be full of water. Lower the bowl away from the housing cap, empty all the water into a spare bucket or bowl and remove your old cartridge before wiping the bowl clean and rinsing it out.

Step 3 – Check that your O ring is in good condition. This is the ring that provides a waterproof seal on your unit so if it looks like it’s worn away you might need to replace it or at least give it a coat of silicon grease.

Step 4 – Remove your new cartridge from its wrapping and place it in the housing bowl, slipping it snugly onto the pipe in the bowl’s base. Then screw the housing bowl onto the cap until it’s nice and tight (but not too tight).

Step 5 – Turn the stopcock back on and let the system refill. When it’s full, close the tap and check the bowl for leaks, tightening the bowl if you notice any. Note that you might need to turn off your water and release the pressure again at this point.

Step 6 – Open the tap up and let the water run through it for at least five minutes to flush out any remaining debris.

And that’s it, you’re in the clear. But remember, don’t feel guilty for giving up and calling a plumber, as if you make a mistake at any point in the cartridge replacement process, it can end up being a very expensive mistake indeed.