How do I Install a Shower Drain Attached to a Sink Drain?

Sewer pipe is made from hard plastic, for durability and toughness.

Every house has a main sewer line that runs into either the city sewer or a septic tank. Most water fixtures that have sewer pipes to take their waste water away, run into this main sewer line. However, if city permit laws allow, one fixture's sewer pipe can attach to another fixture's sewer pipe before the first sewer pipe runs down to the main sewer line. Sewer pipes are attached to one another by connecting couplings, and are held in place with glue.

Things You'll Need

• Felt tip pen
• Tape measure
• Hacksaw
• Tradesman's knife
• ABS glue
• ABS connecting coupling
• ABS sewer pipe
• T-shaped ABS coupling
• ABS P-traps, 2
• Bracing and joist nails
• Hammer

Instructions

1. Mark the main sewer line where the shower sewer pipe will attach into it. Make a second mark 3 inches along from the first. Cut through the main sewer pipe at both marks using a hacksaw. Be sure that the cuts are straight, and remove burrs with a tradesman's knife.

2. Apply ABS glue around both cuts in the pipe, and also the inside ends of an ABS connecting coupling. Push the coupling between the two cuts, making sure that the coupling's side spout is facing up. Hold in place for 30 seconds. Apply glue to the end of a new piece of ABS pipe. Also glue the inside rim of the connecting coupling's spout. Push the pipe into the spout rim and hold for 30 seconds. Measure, mark, cut and apply glue to new pieces of pipe and attach it to the newly installed pipe until you reach the point where the shower pipe connects to the sink pipe. Mark the sink pipe at this point.

3. Cut through the pipe at the mark and remove burrs. Measure and cut new pipe to run from this point up to the sink. Apply glue to the end of the newly installed pipe, and one end of the pipe that will run over to the sink. Also glue the inside ends of a T-shaped ABS connecting coupling. Push the coupling onto the end of the newly installed pipe and push the pipe leading to the sink into the other end of the coupling. Hold in position for 30 seconds.

4. Slip a P-trap over the end of the pipe leading over to the sink. If the vertical part of the P-trap is directly under the sink drain pipe, take the P-trap off and glue it to the end of the pipe. Push the sink drain pipe down into the other end of the P-trap and secure it with the P-trap's nut.

5. Glue the end of a piece of shower sewer pipe and the remaining inside end of the T-shaped coupling. Push the pipe into the coupling and hold for 30 seconds. Now install new shower pipe over to below the shower base flange. Push another P-trap onto the end of the pipe. Again, if the vertical part of the P-trap is directly below the shower base flange, take it off and glue it to the end of the pipe. Wet around the shower base's rubber flange, and the end of the vertical part of the P-trap. Push the P-trap all the way up into the flange.

6. Add bracing to any parts of the new sewer pipe that needs support.

Tips & Warnings

• A connecting coupling has the same diameter as the pipe it will attach to, and its side spout is the same diameter as the pipe that will run into it.

• If the vertical part of the P-trap won't reach up into the shower base flange, cut a new piece of sewer pipe to length so that one end pushes up into the flange and the other end reaches down to the end of the P-trap. Glue the P-trap and pipe together using a straight ABS coupling.

• All horizontal sewer lines need to be installed at a gradient to allow waste to travel along the pipe. Check with local city laws regarding the correct gradient in your area.

• ABS (Acrylonitrile Butadiene Styrene) is a hard black plastic used to make sewer pipes.

• If installing PVC sewer pipe, first prime all joints with PVC primer and use PVC glue.

• Check with local city codes for the correct diameter pipes needed for both the sink sewer pipe and shower sewer pipe.

References

• "Home Improvement 1-2-3"; Benjamin W. Allen, Christopher Cavanaugh; 1995