Venting Problems and Sewer Gas

To understand venting, the definition of a venting system is:

Piping installed to equalize pneumatic pressure in a drainage system to prevent trap seal loss or blow-back due to siphoning or back pressure.

 

That is to say, if your venting is not installed correctly, the gasses and smells from your septic tank and associated piping will leak through into your home. When a toilet is operated, the waste water displaces the air in the piping and forces it to escape from the piping. Normally the traps are installed to stop this escape and directed outside through your vent stack, without properly designed venting, the escaping gasses will bubble through the trap. This will render your traps useless until the trap is refilled with water. Of course any fixtures not trapped will always allow gases to escape.

In Costa Rica you will often notice these gas smells in your kitchen sink while people are showering. The showers are rarely if ever trapped.

How to spot a home without proper venting:

Smell in the living areas.

Lack of vent piping penetrating and venting above the roof.

Sound of water running through the pipes in fixtures not in use.

Modified 07.19.2009