a pressure vessel of the type used in domestic water purifying systems for the filtering of potable water , wherein an uncompromised , spherically ended cylindrical pressure vessel housing is provided which is manufactured of a very strong high quality resin and comprises two detachable major sections sealed with an o - ring and secured together through provision of a threaded annular collar ; quick connect type plumbing fitments are provided at an inlet port and an outlet port of the pressure vessel housing requiring no tools to facilitate the removal and attachment thereof ; a decorative plastic shell manufactured of less expensive resin is provided to encase the pressure vessel to provide structural stability and which can be fabricated to also provide aesthetic flexibility with regard to shape and color and may also provide a compartment for incorporating an electric flow meter .