What Is the Plumbing for a Bathtub and Shower?

Drain Shoe

• The drainpipe that runs vertically under the bottom of the tub is called the drain shoe. One end of the drain shoe connects to the main opening in the tub, with a drain body that screws into the drain shoe opening. Since the drain body sits inside the tub, tightening it keeps the drain shoe’s opening lined up with the opening inside the tub. The other end of the drain shoe connects to a pipe tee, which also threads onto the large drainpipe roughed in previously.

Overflow Tube

• The overflow tube is the drainpipe that captures any of the water that rises to the level of the overflow drain opening in the tub. Because of its function, the overflow tube runs vertically behind the end of the tub and connects to the pipe tee below. The screws that go through the overflow drain cover anchor into the opening of the overflow tube, helping to keep the top of the tube anchored against the tub.

Stopper

• If your bathtub has a built-in stopper mechanism, the stopper runs down the overflow tube. Plunger-style stoppers have a plunger on the end of the linkage that runs down the overflow tube. As you move the stopper’s lever, the plunger lowers into the pipe tee and blocks off where the shoe drain connects, stopping any water from flowing further. With pop-up stoppers, the linkage in the overflow tube pushes on another linkage that runs up the drain shoe and connects at the other end to the stopper inside the drain body.

Faucet

• The shower and tub combination uses the same faucet. The faucet may have anywhere from one to three control handles that control the flow of water through the faucet. The handles connect to a valve assembly, which may be a valve stem that has washers and other parts that can wear out, a cartridge you must completely replace when the faucet leaks or springs and rubber seats or seals that regulate the water’s flow. On more modern faucets, the diverter sits inside the tub’s spout, and you control it by moving the rod in the spout. With older faucets, you twist the middle of the three handles to control the diverter, switching the flow of water from the tub spout to the shower head.

Water Supply Lines

• Separate hot and cold water supply pipes feed into the faucet assembly, where the faucet mixes the hot and cold water according to the settings you choose using the faucet handles. Another supply line connects to the top of the faucet assembly inside the wall and runs up to the curved pipe the shower head sits on. When you activate the diverter, the water climbs up the vertical supply line, which is why there is a delay before the water comes out of the shower head.