How to Find a Clog in Drain Pipes

Each drain in your home connects to a main sewer or septic line. Because of this, there are multiple points where your drain or pipes could be clogged. Locating the clog in your drain is the most important step in unclogging your drain because it determines the best method for cleaning your pipes.

  1. Start with the plumbing fixture that is highest up in the house. For example, begin with the second floor bathroom. Run the water and see if it clogs up. If it does not clog, move on to the next step. If it clogs immediately, it is probable that the clog is in that sink's drain or trap.
  2. Move to the next lowest sink or fixture. Check toilets and shower drains as well. If several drains are clogged but others are not, then the clog is on the branch line that links these fixtures to the main line.
  3. Check the lowest points of the system. If the lowest plumbing fixtures are clogged or all of the fixtures are backed up, it is likely the main stack or sewer line that is clogged.


  • You can clear clogged drain traps by pouring ¼ cup baking soda, ½ cup white vinegar and then 1 qt. of hot boiling water down the drain.


  • Contact a plumber if your main stack or sewer line is clogged.

About the Author

Jack Busch graduated from University of Iowa in 2007 with a Bachelor of Arts in English with honors and has been publishing web content ever since. He has contributed to groovyPost.com, 7Tutorials.com, PrimerMagazine.com and various other tech websites. He also co-authored "Network Your Computer & Devices Step by Step" (Microsoft Press).