Manufacturers print an interval on the box. It is a starting point, not an answer — how fast a filter exhausts depends on how much water goes through it and what is in that water.
Typical intervals by type
Why household size matters more than the date
Filters are rated in litres or gallons, not weeks. The calendar interval on the packaging assumes average use. A household of five drinking, cooking and filling bottles will exhaust a cartridge in half the stated time. A couple who mostly drink tea may stretch past it.
If your filter has a rated capacity, that number is more useful than the date. Divide it by roughly how much you get through in a week.
Signs a filter is overdue
Taste is the obvious one — if chlorine is coming back, the carbon is spent. Slower flow means the filter is clogging with sediment. Cloudiness, or ice cubes that suddenly taste of the freezer, point the same way.
One thing worth understanding: an exhausted carbon filter does not simply stop working. Trapped contaminants can begin releasing back into the water, and the damp carbon bed is a hospitable place for bacteria. A filter left in for a year is not neutral — it can leave you worse off than no filter at all.
Do filter indicator lights help?
Mostly they are timers, not sensors. They count days or dispense cycles since the last reset, and know nothing about what is actually in your water. Treat the light as a reminder and your own taste and flow as the real test.
Buying replacements
Order by part number, not brand. Cartridge shapes vary between models of the same manufacturer, and “compatible” is not the same as “fits”.
Our guide to refrigerator filters → · Browse replacement cartridges on Amazon.ca →
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