The Essick Air D46 720 has a 1040 wick that must be changed at least once per season. The water panel is easily accessible and is located at the bottom of the unit behind the grill. To remove this grill, push down on the tabs on either side of the humidifier. The wick is secured in the unit with a latch. Push up on this latch and pull the wick out. Dispose and insert your new 1040 wick – placing the bottom in first. There are two wicks in this humidifier, one on the front and one on the back. Make sure you repeat these steps on the back grill when you are finished with the front. Remember, the replacement wicks for this unit are the Essick Air 1040 and they should be changed once per season of use and possibly more often if you have hard water.