Sewer Gas: Finding And Fixing That Rotten Smell In Your Basement

There’s not a lot to like about the presence of sewer gas in your basement, besides just the odor. Sewer gas contains toxic and non-toxic gasses caused by the decay of household wastes in the sewer pipe. The toxic components, which can cause illness or even death in sufficient concentration, are mostly ammonia, hydrogen sulfide and methane. The last two are flammable and explosive as well. The gas may infiltrate a basement through a number of routes. If you suspect a high concentration of gas from your home's sewer system, you should evacuate the area and call for professional assistance. These are some of the possible sources of sewer gas:

  • The trap in an unused basement floor drain may have gone dry, admitting sewer gas into the room. Water in the trap normally functions to seal the gas out. However, evaporation from a long period of disuse may empty the trap. This can be remedied by pouring a bucket of water down the floor drain. 
  • Look for any missing clean-out access plugs that lead to the sewer line. Sometimes a clean-out plug inside a basement floor drain may have fallen out unnoticed or been removed and not replaced. Remove the drain grate and look into the drain bowl for a missing plug.
  • If there is a basement bathroom, check for a faulty wax seal between the toilet base and the toilet flange. Sewer gas can penetrate the seal and enter the basement.
  • Gas pressure in the sewer line normally escapes harmlessly through pipes that vent at the roof. Bird’s nests or other blockages in the vent pipe can cause pressure to build in the sewer line. Pressure may be sufficient to force sewer gas through the water in drain traps or other barriers which are normally effective. Also, vent pipes inside the wall may corrode or separate at joints, leaking gas into the premises.

Joe Behr Plumbing & Heating has served the mid-Ohio region since 1965. Let us do the same for you with experienced sales, service and advice.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information about sewer gas and other HVAC topics, visit our website.

Joe Behr Plumbing and Heating, Inc. services the Mid-Ohio area. 

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