Most household water filters last between 1 and 12 months, while reverse-osmosis membranes may last 1–3 years. Replace each filter when it reaches its rated litre capacity or maximum service period, whichever comes first. Always follow the instructions for your specific model.
Typical replacement intervals
These ranges are general guides only:
| Filter type | Indicative interval |
|---|---|
| Water-filter jug cartridge | 1–2 months |
| Tap-mounted filter | 2–3 months |
| Refrigerator filter | About 6 months |
| Under-sink carbon cartridge | 6–12 months |
| Reverse-osmosis prefilter | 6–12 months |
| Reverse-osmosis membrane | 1–3 years |
| Whole-house cartridge | 3–12 months |
Cartridge size, filter media and litre rating vary between models, even when the filters appear similar. Reverse-osmosis prefilters usually require replacement more often than the membrane, so follow the schedule for each filtration stage.
What shortens filter life?
A cartridge may need earlier replacement because of:
- High water use: More litres processed means the rated capacity is reached sooner.
- Sediment: Particles can clog the cartridge and reduce flow.
- Incoming water quality: A higher contaminant or sediment load can exhaust filter media faster.
- Undersizing: A small cartridge may reach capacity quickly in a high-demand household.
- Overdue prefilters: These can increase the load on later filtration stages.
A cartridge may look clean even when its media is exhausted. This is particularly relevant to activated carbon, which can lose adsorption capacity without an obvious visual change.
When should you replace the cartridge?
Replace it at the rated capacity or maximum service period, whichever occurs first. Replace it earlier if the manufacturer specifies this or you notice reduced flow, unusual taste or odour, discolouration, visible sediment or cartridge damage.
These signs can indicate that replacement or assessment is needed, but taste, smell and appearance alone cannot confirm drinking-water safety or filter performance. Record the installation date and monitor litres used where practical, or use the system’s replacement indicator.
Plumbed-in filters are connected to a pressurised water supply. Do not open a housing unless you can safely isolate the supply and follow the manufacturer’s instructions. If isolation is uncertain or the housing leaks, keep clear, isolate the water only if it is safe, and contact our Sydney water-filter servicing team.