A damaged drain pipe causing a leak can waste water, increase the water bill, allow hazardous sewer gases to leak in the bathroom and home, and cause water damage in the bathroom. When the drain pipe connected to a bathroom sink develops a leak, the drain pipe may often have to be replaced. You can do this yourself, however, if you are uncomfortable with the project, or the project may be more complicated that you thought, it is wise to call in a plumber.

The drain pipe parts that are located under your sink includes two central parts - the straight tail piece that is connected to the drain, and the curved P-trap which prevents back up of water and it keeps sewer gases from leaking into the home.Below is a guide on replacing a drain pipe in a bathroom sink:1. Turn off the main water valve below the sink that allows the water to flow, or turn off the main water supply which is normally in the basement or at the water meter.2. Clear out any clutter of items under the bathroom sink because you are going to need the room to maneuver pipes as you remove the old ones and install the new ones. Set a container or bucket underneath the P-trap.

Loosen the two nuts on the end of the P-trap.3. Gently remove the P-trap from the other parts of the drain pipe. Slide the P-trap downward and into the bucket. It will be filled with water that has a bad odour so let it spill in the bucket. Wipe up any excess water that may have spilled on the floor.4. Find and remove the nut to the tail piece and then remove the pipe. Then find and take out the nut that attaches the pipe to the drain pipe and remove it.5. You should have already have purchased a new drain pipe kit. Wholesale Pop Up Basin Wastes Factory Take out the kit and its parts. Check the length of the new tail piece to make sure it matches the old pipe.

If it is not the same length, it may have to be cut.6. To prepare to install the new P-trap, put the top nut of the new P-trap on the end of the tail piece. Position the P-trap so that the nuts on the other pipes will fit to them securely. Slip the new P-trap into place between the tail piece and the sewer pipe. Find the nut that secures the entire drain pipe and tighten it.7. Retighten the jamb nut after the P-trap is in place. Tighten the nuts at either end of the P-trap.8. Turn the water back on and open the faucet to allow the water to flow. Check the pipes to make sure there are no leaks.It is not difficult to replace a bathroom sink drain pipe; however, you should be comfortable with the project and understand the installation process. If you have concerns, you can always hire a professional plumber.