Clearing Out a Clogged Main Drain

A clogged drain.
  • 1-3 hours
  • Beginner
  • 0-100
What You'll Need
Plumbing snake

Dealing with plumbing issues is rarely fun and often dirty but it's important to keep your drains flowing smoothly, especially the main drain. Blockages in the main drain pipe from your home can lead to numerous problems so you should deal with a clogged pipe as quickly as possible. To save you calling in a professional, try using this guide to solve the problem.

Step 1 - Find Blockage

The first thing you need to check is whether it's a single drain that is causing the backed up plumbing or the main drain. If your bathroom sink is clogged, try checking whether the bath is draining correctly. If it is not, you need to investigate the plumbing fixtures in other rooms such as the kitchen or laundry room. A blockage in the main drain will cause problems in all of the fixtures. If you isolate the blockage to a single appliance or room, a plunger is an excellent tool to clear the blockage. Cover the drain with the plunger and move it up and down. The airtight seal that occurs will force whatever is clogging the drain to be dislodged so that the water can begin flowing again.

Step 2 - Access Main Drain

If the blockage is in the main drain pipe, you will need to find the access point. This is a “Y” shaped pipe normally found close to ground level outside the house or garage. The access cap has a square fitting on top. Before using a wrench to remove the cap, you need to position a bucket to catch any overflowing waste-water that has accumulated in the pipes and make sure that no-one in the house will use any of the plumbing facilities. Remove the cap slowly to minimize spillage of the waste.

Step 3 - Remove Blockage

If you don't have a plumbing snake, you will be able to get one from a tool rental outlet. Insert the plumbing snake into the drain outlet and feed it into the pipe until you find the blockage. Hook the snake onto the blockage by twisting the handle then move the equipment back and forward to break up the obstruction and clear the drain. Run the snake through the pipes the other way just in case there are any other blockages that have formed.

Step 4 - Access House Trap

If you don't find a blockage in the pipe, you can also check the house trap. This “U” shaped pipe is buried underground but will have two clean out plug caps (similar to the one on the main drain pipe) situated next to each other. Use the wrench to remove the cap closest to the outside sewer. If water doesn't begin to flow out of the drain, use the plumbing snake to search for a blockage between the house trap and the main drain pipe. If water seeps out as you unscrew the cap and check very quickly to see if you can remove the blockage yourself with the snake. If you can't, you should close the cap and call a professional to deal with the problem and prevent any potential water damage to your home.