How to Install a Bathroom Drain Waste Vent System

Most Common Mistakes

1. Violating or ignoring code restrictions,
2. Not installing D/W/V with at least a 1/4" slope per one foot pipe,
3. Not properly venting or trapping all fixtures,
4. Attaching too many fixtures to a drain or vent pipe,
5. Using pipes that are too small,
6. Not providing enough cleanouts or not providing cleanouts at the prescribed places,
7. Venting the fixture too far from the fixture's trap,
8. Not properly aligning tubing into fittings or stop valves. (Forcing the nut onto the compression ring at an angle when the tubing is at an angle will cause a leak.)
9. Using a fitting in a wrong position,
10. Installing rough plumbing in the wrong location,
11. Reducing pipe size as the pipes run downstream,

12. Cutting pipe too long and not allowing for the ridge in the fittings, and
13. Forcing the trap and waste arm fittings out of alignment and putting too much stress on the nuts and washers in the tubing.
14. Make certain the compression tubing is put in the fittings so that it is evenly tightened.

Installing Drain Waste Vent Pipe

Running the pipe can be tricky. All different kinds of fittings are available to turn in different and receive different sizes of pipe at various angles. One fitting may need 3 opening ports, all accommodating a different size pipe. You will have to plan your runs and buy the necessary fittings (always get a few extra). Keep in mind that codes may regulate how fittings can be used (i.e. sanitary tees may not be used in vertical to horizontal connections; long sweep connection must be used here). You will need to know the diameter of your pipes, their angles, the code and their direction to determine each fitting.