Unclogging Your Basement Main Drain From The Cleanout

In this post, we’re going to show you just how simple it is to unplug your main house drain from the cleanout without using a plumber.

First, open the main cleanout.  This is a Y-shaped fitting near the bottom of the soil stack or where the drain leaves the house.  Set a bucket underneath the cleanout plug and lay rags around to catch the flood that may occur.

Use a pipe wrench to unscrew the plug counterclockwise.  If the plug does not turn, first try working penetrating oil into the threads, then slide a section of pipe over the wrench to increase your leverage.  As a last resort, nick the plug’s edge with a cold chisel and–keeping the blade in the nick–hammer the plug around.

Remove the plug completely and mop up the flood.  using a drain-and-trap auger long enough to reach the sewer outlet, probe and remove the obstruction, then flush with a hose.  Coat the plug with grease or pipe compound and recap the cleanout.

To get at your main drain from the house trap instead, first locate the fitting.  You can identify it from two adjacent cleanout plugs, visible at floor level if the main drain runs under the floor.  Spread heavy rags or stacks of newspapers around the trap to prepare for flooding, then slowly loosen the plug closest to the outside sewer line.

If no water leaks out as you unscrew the plug, the clog is in the trap or the main drain between the trap and the main cleanout and may be fairly easy to remove.  If water seeps out, probe the drain beyond the house trap with an auger.  Unless you can remove such a blockage quickly, recap the plug and call a plumber.

When working from the trap, first unscrew the trap plug completely and feed an auger through the trap toward the main cleanout, but probe gently.  Do not attempt to free the blockage all at once, as you would when working from above, but poke a small hole in it.  Wait for water to drain down gradually, then break up the blockage with repeated jabs of the auger.

After the flow subsides, open both house trap cleanouts and scrape out any remaining sludge with a wire brush. (If the clog is not in the trap but in the main drain between the trap and the cleanout, remove the second trap plug and feed the auger toward the cleanout, following the same precautions.)

Recap the house trap cleanouts and insert a hose into the main cleanout to flush the main drain.  Then, replace the cleanout plug and you are finished!