Yes, opened Brita filters do expire. The moment the filter first comes into contact with water, the clock starts counting down until its expiry date.
If you continue to use a Brita filter beyond the recommended filter replacement date, you’ll increase the risk of very slow filtration speed and bacteria growth on the filter.
Recontamination of water is another dangerous risk of using an expired filter in your Brita pitcher. If the filter degrades significantly, the media may develop holes, allowing contaminants and unfiltered water to bypass straight through.
Brita filters last between 2 and 6 months, depending on the filter in question.
To help sustain your unused Brita filter’s indefinite lifespan, make sure to store the filter correctly. The ideal storage location for a Brita water filter is a cool, dark cupboard, away from any sources of heat or moisture.