If the water level in your inground pool is too high, this may be a sign that the filter isn't clean. You will also need to lower the water level when preparing for the winter months. It is better to lower the water level than to empty the pool completely, in order to prevent any pipes and pumps from freezing and breaking. Lowering the water level can take from an hour to several hours depending on which method you use. .
Make sure the inground swimming pool water is clean. Remove any floating debris with a net. Set the filter to "backwash," then clean the filter. The water level in the pool may go down simply by cleaning the filter.
If cleaning the filter did not lower the water level enough, or if you are winterizing your pool, purchase or rent a submersible pump from a hardware or home improvement store such as Lowes or Home Depot.
Add a chemical treatment to the pool. If you are preparing your pool for the winter months then you will need to clean the water with chemicals consisting of chlorine, winter alkalizer, and winter powder. This will help keep the water clean throughout the season. Outside of winterizing your pool you add chlorine, an algicide, and super shock throughout the months you are using the pool. Consult the Resources (below) for more information about proper pool care.
Connect the submersible pump to the drain hose of the pool. This is located near the pool pump on the side of the pool. Place the hose to the submersible pump in the deep end of the pool. Plug it in to begin pumping water out. Check the water level frequently and disconnect the pump when the water is at the desired level. If winterizing, you will want to bring the water level down below the skimmer (the opening through which water flows to reach the filter). Remove the pump.
Place a floating device in the center of the pool, such as an inflatable winter pillow that can be found in any pool supply store. Then cover the pool with a pool cover. This will enable any ice that may form throughout the winter to go toward the middle of the pool rather than the edges close to the walls. If ice forms on the walls of the inground pool it could damage the support of the walls in later months.