The present invention relates to a point-of-use water treatment system unit (10). The unit (10) includes a filter housing assembly (60) having a filter tank assembly (66) and a closure (64) which utilizes a handle (152) and cammed reciprocating lock blades (146, 150) to secure the closure (64) to the filter tank assembly (66). A UV tank assembly (300) includes a planar baffle plate (322) and a vaned baffle plate (324) to induce plug flow about a UV lamp assembly (280). The UV lamp assembly (280) is used which simultaneously electrically and sealingly mounts to UV tank assembly (300) and electrical cap assembly (290) using a bayonet mount. A bi-planar manifold assembly (40) is used to interconnect components of the WTS unit and to provide an envelope for accommodating a water pipe assembly (34). The bi-planar manifold assembly (26) enhances the compactness of the design of the WTS unit (10). Also, a support plate (26) is disclosed which provides support to subcomponents of the WTS unit (10) while also dissipating heat from a UV tank assembly (300).