How to Install a 2-Inch PVC Shower Drain

Installing PVC sewer pipe for a shower is a fairly simple process once you make sure that the main sewer line is accessible to tap in to.

Shower sewer lines are easy to install if care and attention are given.

Difficulties can arise if there's little space to crawl in to under the floor joists, and it's always best to make sure that you can first work in the confined space before starting the job.

  1. Unscrew the nut and rubber washer from the bottom of the shower drain fitting and apply some plumber's putty around the underside lip of the top of the drain fitting. Drop the fitting into the hole in the shower base (the putty should be between the shower base and the shower drain fitting). From underneath, place the rubber washer and nut back on the fitting, and tighten.

  2. Push a piece of 2-inch PVC sewer line (about 12 to 16 inches long) up into the shower drain fitting from below (don't glue anything yet). Then attach a P-trap (with the long pipe pointing vertically) up to the sewer line, using a 2-inch coupling. Point the other end of the P-trap toward the existing sewer line.

  3. Work your way towards the existing sewer line, cutting the line and adding couplings as required. Make sure you connect the vent line to the sewer line, as stipulated by your local permit office. When you reach the existing sewer line, you will need a larger coupling the diameter of the existing sewer line that also has a 2-inch "spout" for the new sewer line to attach to.

  4. Cut into the old line and connect the new sewer line. Check that the required gradient is correct, and if necessary shorten the 2-inch line that is pushed vertically up into the shower drain fitting.

  5. Check that the new PVC line is correct before priming and gluing every coupling in place. Strap the new line to the bottom of the joists for support, if necessary. Wipe away any excess plumber's putty from the top of the shower drain fitting.

  6. Tip

    Make sure you know local regulations regarding the distance between the gas vent line and the shower fixture. P-traps are shaped to hold water that acts as a barrier between your home and sewer gasses. The new 2-inch PVC sewer line should have a downward gradient as it travels towards the existing sewer line. This allows gravity to "push" sewer water down the pipe. The required gradient can be different in certain areas: check with the local permit office to find the required gradient. After priming each joint, wait a few minutes before gluing; hold each glued joint together for 30 seconds to allow it to bond well. Have on hand a supply of different 2-inch PVC couplings: straight, 30, 45, 60 and 90 degree couplings.