How Often to Change a Water Filter Cartridge

A water filter cartridge does not last forever. Over time the filtration media becomes saturated with the contaminants it traps, and an exhausted cartridge can actually release captured particles back into your water. Replacing on schedule keeps your water clean and protects the seals in your system from pressure build-up.

Recommended replacement intervals

Intervals depend on cartridge type, your water hardness and how much water your household uses. The figures below are a general guide — always defer to the manufacturer's recommendation for your specific system.

Signs your cartridge is overdue

• The taste or smell of chlorine returns to your filtered water.
• Water flow from the filtered tap slows noticeably.
• Limescale starts reappearing on your kettle (for limescale cartridges).
• The water looks cloudy or has a faint discolouration after sitting.

Does water hardness affect cartridge life?

Yes. In very hard water areas such as London and the South East, a limescale cartridge will saturate faster than its rated life because it is trapping more mineral. If you live in a hard water region, consider replacing limescale and sediment cartridges every four to five months rather than six. See our guide on UK hard water areas to check your region.

How to change your cartridge

Turn off the water supply to the filter. Unscrew the filter housing, remove the old cartridge and discard it. Rinse the housing with clean water, insert the new cartridge, and re-tighten the housing by hand. Turn the water back on and run the tap for three minutes to flush the new cartridge. Reset the replacement reminder on your system if it has one.