Why is water dripping from the red button on my water filter?

The red button is a spring-loaded air release valve which is used to purge the air from inside the filter bowl after changing a cartridge. Purging the air avoids having trapped air forced through your household plumbing and being blown out at the faucets.

Although it is rare, sometimes this air release valve will leak a little water right after a filter cartridge change out. This is almost always caused by a very small particle of foreign debris (sand or silt) getting stuck between the rubber seal and the valve seat.

Most often the leaking can be resolved by simply depressing the red button and wiggling it side to side to dislodge the particle. This can be repeated several times to flush out any foreign debris that may be causing the leakage. NOTE: To avoid water from spraying everywhere when you depress the button you can cover the filter head with a towel or plastic bag.

You can also try to get it to seal by pushing the valve seat up against the seat from the underside of the cap. Use a screwdriver to push on the screw head inside the filter head where the air valve is located. If this does not work after several attempts, the air valve can be removed, and the seal and seating area can be cleaned and reinstalled. Make sure the screw is fully tightened as this increases the tension on the spring, increasing the closing force. This cleaning method is very effective.

In the rare event both these options fail there is a chance that the air valve seat has somehow been damaged or the spring has weakened. In this case the air release valve may have to be replaced, however this should be the last resort.

TIP:

If you find that your air release button is problematic to seal, there is another option to get air out of the cannister and the water line after a filter cartridge change. When you have the valve sealing properly don't push the red button again, but instead open a faucet in your house that is closest to the filter outlet for around 5 minutes to let air circulate out. If the red button still leaks, you may have to try a few times. Often if it leaks just a little you can place a bowl under the filter, and it often stops after a day or so. Then, you can avoid leaking issues in the future by always using the open faucet method to work the air out instead of using the air release button. There will still be some air bubbles for a while, but they will work themselves out after a couple of hours of water usage.