Aqua-Pure whole house water filter systems point of entry systems that are installed where your water line enters your home. Depending on your needs, Aqua Pure’s whole house filter systems are used for filtering sediment, taste, and odor from your home drinking water. As a general rule, AP801 is used for homes with 2-3 bathrooms, AP802 for homes 4-5 bathrooms, and the AP902 &AP903 for homes with 5 or more bathrooms. Replacing your Aqua-Pure whole house water filters regularly ensures you are getting the highest quality water in your home.