Broken House Sewer Trap & How To Use Sewer Trap
June 22, 2013


A homeowner in Astoria Queens was alarmed as she continued to smell a foul odor coming from the area in her basement where the sewer trap was located.  After three consecutive days she decided to lift the cover when she observed a portion of the sewer pit to be covered with sewage.  She decided to call her plumber to diagnose the problem; he began by snaking the sewer line and told her that the line had a minor backup which he had cleared.  The homeowner decided to check the sewer pit the very next morning when she noticed the same exact occurrence, she called the plumber back again when he performed a camera inspection of the sewer line.  The entire sewer line going out to the roadway was clear, it turned out that the bottom of the trap was rotted due to over 65 years of usage.


Harris water Main & Sewer Contractors was hired to replace the existing trap with a new 4” cast iron trap which was re-connected to the house piping and fresh air vent the very same day.  The homeowner no longer had a foul odor in her house and resolved the issue without having to replace the entire sewer line as she was advised to by several plumbers.

What is the primary function of a sewer trap?

  1. To hold water forming an airlock against sewer gases and odors from escaping into your home.  If your sewer line has not been used for an extended period of time you should run water in your home, there is a good chance the water has evaporated.
  2. To serve as an entrance point when a sewer line needs to be cleaned or have a video inspection performed

What is the importance of a double vent trap?

A double vented sewer trap allows for easy access when cleaning the line towards the house or out of the house towards the roadway.  It is possible that your sewer line has a single vent trap which is much more challenging when trying to clean the line as the entrance point does not easily accommodate both ends of the sewer line.  It is also possible that your sewer line does not have a trap; in this case a section of the pipe near the foundation wall would have to be opened for the installation of a new sewer trap.

Important facts when opening the sewer trap

It is very important to always open the sewer cap that is closer to the front of your home.  If you find a sewage backup it will flow directly into the open cap and go directly out to the public sewer.  If the cap on the house side of the trap is opened first, it will have no direct route to escape resulting in a mess inside your home.