Plug member used in hydraulic testing of plumbing system

A method of hydraulically testing a drain, vent, waste plumbing system comprising the steps of

• (a) installing a shallow, cup-shaped, sealing element, comprising a circular disc, an upstanding, cylindrical sidewall extending upwardly from the perimeter of the disc and an angled flange extending outwardly and upwardly from the upper end of said cylindrical sidewall, in the upstream end of the straight through barrel of a plastic tee, such that the cylindrical sidewall of said cup-shaped, sealing element is coaxially received in the barrel of the plastic tee and the flange on said cup-shaped, sealing element mates with and lies flatwise against the bevel in the barrel of the plastic tee;
• (b) installing the plastic tee of step (a) into the draing, vent, waste plumbing system;
• (c) filling the drain, vent, waste plumbing system upstream of the plastic tee which contains the sealing element to hydraulically test the drain, vent, waste plumbing system;
• (d) breaking a hole in the bottom of the sealing element to release the water in the drain, vent, waste plumbing system;
• (e) breaking the disc from the cylindrical sidewall of the sealing element and removing the disc from the side entry of said plastic tee;
• and
• (f) prying the remaining cylindrical sidewall and flange of said sealing element from the barrel of said plastic tee and removing said cylindrical sidewall and flange from the side entry of said plastic tee.