How to Run Pex Tubing to a Toilet

PEX is a type of semiflexible polyethylene tubing. Since its development in the 1960s, PEX usage has increased to include a wide variety of home plumbing projects. Its flexible nature makes it ideal to attach to the rear of a toilet and supply fresh water from the water valve on the wall. Attaching PEX tubing to a toilet requires little time, since PEX toilet adaptors come with the end couplers already installed.

Unscrew any existing valve or cover from the water supply pipe in the wall behind the toilet, if applicable. If you are connecting a new toilet that does not yet have water, the pipe may not have a cover on it.

Open a one-quarter turn ball-stop water valve. Unscrew the nuts from both ends of the valve and set them aside.

Turn the valve so that one outlet faces toward the wall and the other upward toward the toilet. Push the valve into the water pipe in the wall until it meets the pipe’s compression nut. Hold the valve in place and turn the compression nut counterclockwise tightening it over the valve’s threads.

Place an open-ended wrench on the compression nut and another open-ended wrench on the rear of the valve. Turn the compression nut another one-half turn tightening it while holding the valve still with the other wrench.

Examine the PEX toilet supply hose and locate the end with a black rubber stopper. Insert that end into the back of the toilet water supply outlet. Hold the hose in place with one hand and turn the plastic coupler at the top clockwise until it is tight. Place an open-ended wrench around the coupler and turn it another one-quarter to one-half turn ensuring a tight seal.

Screw the other end of the toilet supply hose to the upper outlet on the water valve and tighten it using the wrench.

Turn the main water supply back on for the home and open the toilet water supply valve to check the PEX tubing for leaks.