Whole house filter housing parts are a member of the water filter parts family. These filter housing parts assist with the installation and maintenance of your whole house water filter system. Our filter housing parts include cartridge couplers, filter housing caps, filter housing sumps and pressure relief buttons. All of these products have their own specific purpose. Cartridge couplers extend the length of your filter, filter housing caps stop the flow of water at an end location, and filter housing sumps hold water at the bottom of a filter.