How to Vent a Bathroom Sink & Toilet

One of the most effective and easiest methods of venting a sink drain and toilet is installing an air admittance valve on the drain line. Each plumbing set-up is different, but in most cases, the logical place to install this valve is right after the sink's drain trap, which is the U-shaped fixture just below your drain pipe. You can install this anywhere on the drain line and still vent the sink properly. The valve will allow air into the pipes as it is sucked out when the drain water starts flowing.

Hacksaw
T-fitting
PVC cement
Air admittance valve

Instructions

- 1
  Find the back of the drain pipe on the sink or another suitable place to install the vent valve, which is called an air admittance valve. There must be sufficient space to access the drain and work on it comfortably.
- 2
  Cut into the drain line with a hacksaw at the point where you wish to install the air admittance valve.
- 3
  Install a T-fitting between the two sections of pipe on either side of the cut you just made. If necessary, remove a small portion of the drain pipe about 2 to 3 inches long by making another cut into the pipe with the hacksaw a few inches back from one end. Perform this step only if the T-fitting will not fit between the two pipe sections.
- 4
  Spread PVC cement on the ends of the T-fitting and the pipe. Place the T-fitting on the pipe. Install the air admittance valve into the open end of the T-fitting, so the valve is positioned vertically on the drain. Let the cement dry for four hours or as indicated on the label.

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