Abstract: The invention relates to a unitary, one piece plumbing pipe for use as a drain and vent pipe. In particular, the invention can be used to drain a single appliance using the typical goose-neck style drain pipe, but it can also vent an entire plumbing system. The one-piece plumbing vent and drain pipe is quicker to install and replaces many pieces of pipe with a single piece pipe. Furthermore, no vent through the roof of a building is necessary in view of the present invention. The vent pipe has a vertical portion extending upwardly above the highest point of said drainage plumbing, but not through said building to the outside, said vent pipe having an opening capable of permitting ambient air to enter the pipe when there is negative fluid pressure within said pipe, but not permitting any fluid to escape the vent pipe when there is positive fluid pressure within said pipe.