How to Tie into a Main Drain Properly


The main drain, sometimes called the waste drain, carries wastewater from all the other drains in you home. When adding a new bathroom, sink or other fixture that requires a drain, you will need to tie into your main drain.

Tying on to your main drain is probably not something you would want to do yourself. They must be installed according to precise specifications to meet your city codes. The drains have to be sloped correctly so the water can run freely. They also need special fittings so the waste does not get trapped in the pipe when the pipe turns. So what should you expect from your plumber when he comes to tie your new drain on to the main drain.

  • After locating the main drain he will Use a chain cutter or sawzall to cut the existing pipe.
  • He will determine, according to your local codes, the correct slope and size for the new drain.
  • Next he will tie to the pipe using a small piece of pipe and a rubber coupling.
  • For water to flow without gurgling you need an air pipe, or vent. This vent also carries odors out of the house. The drainpipe for every fixture has to be attached to a vent to supply this air. He will also have to follow local codes to know which drains can be connected to the main drain and how far it can travel.

You can see that even though the process itself is not complicated, knowing the size of the pipes, slope of the drain and other factors makes this a job for a professional