When you remove the filter casing, chances are some water will pour out. Place a bucket directly under your filter to catch this water and prevent anything else from getting wet. Your water filter will likely be located near the electrical unit that controls your filtration system. Cover that unit — and any other nearby electrical panels or outlets — with plastic. Use a plastic grocery bag or plastic sheeting to cover any exposed electrical panels. Just make sure there aren't any gaps where water can get in. The exact location of the water shut-off valve will be different depending on the type of system you have and how your home's plumbing is set up. Look for it near the filter. The shut-off valves might look like knobs that need to be turned either vertically or horizontally, or wheels that need to be spun to the right or left. If you're not exactly sure where the shut-off valve is, look up the user or owner manual online. If you're still not sure, you can ask a representative of the company to come out and take a look. At the top of your filter housing, you should see a small red button. This is the pressure release. In order to change the filter, press the button. When you do, a bit of water may come out. That's normal, and the bucket under your filter should catch anything that drips down. Face the handle of the wrench out to the right, away from the housing. Slide the hoop of the wrench up over the housing until it feels snug. Grasp the handle of the wrench and turn it clockwise. It might be hard to turn at first. Apply steady, even pressure on the wrench handle until the housing begins to turn. Depending on where your filter is, there might not be enough room behind it to just continuously rotate the wrench until the filter housing comes loose. If that's true, turn the wrench as far as you can, then slide the wrench off the housing, reset it so the handle is on the right side of the housing, and turn it again. After you've rotated the filter wrench a few times, test the housing's looseness. It should be loose enough for you to unscrew it the rest of the way by hand. Once you get to this point, hold the bucket up as close to the housing as possible. Then unscrew the housing the rest of the way with your hand. Because the housing will be filled with water, it might be heavier than you expect when it finally comes free of the filtration system. Hold the bucket as close to the housing as possible, so that if you accidentally drop the housing, you won't get water everywhere.
Place a bucket under your filter. Cover any nearby electrical panels. Turn off your water. Press the pressure release. Slide the filter wrench up over the filter housing. Turn the wrench from right to left. Reset the wrench and repeat the turn if a wall is in your way. Use your hand to unscrew the housing once it's loose.