How often do I need to replace the filter cartridge in my FloWater Faucet FIlter? The filter cartridge in your FloWater Faucet Filter needs to be replaced every 3 months. Click here for directions explaining how to use the calendar wheel on your FloWater Faucet Filter to remind you when it's time to change the filter cartridge. Related articles How does the FloWater Faucet Filter calendar wheel work? How much does it cost to have the filters in my Refill Station(s) replaced? Can I change the filters in my Refill Station myself? Is FloWater Faucet Filter compatible with my faucet? Does the FloWater Faucet Filter filter out Fluoride?