Abstract: An apparatus for pressure testing a plumbing system having a fluid inlet assembly having an inlet connection, a pressure-actuated flow regulator valve, and a fluid inlet, all made from or lined with corrosion resistant materials. A paddle shaped member is coaxially coupled to a freely rotatable threaded cap member which removably engages the tee fitting in the plumbing system. O-rings along the outer edges of a paddle-shaped member serve to seat the paddle-shaped member into the inner diameter of the tee-fitting and seal the downstream portion of the Y or tee fitting from the upstream portion.