Decomposing waste materials in public and private sewer and septic systems create sewer gases. Methane is the largest single constituent of sewer gas, which includes an assortment of toxic and non-toxic gases, such as hydrogen sulfide, carbon dioxide, ammonia, nitrogen oxides, and sulfur dioxide. Improperly disposed gasoline and mineral spirits may also contribute to sewer gases.
Sewer gases pose the following risks to building occupants:
The design of the plumbing system relies on a connection between household fixtures and the sewer system, which is why a great deal of effort is spent to ensure that waste products -- and the gases that result from their decay -- flow in one direction.
The following failures in the plumbing system may allow sewer gases to flow back into a building:
In summary, the intrusion of sewer gases into the living space should be discovered and fixed before occupants suffer ill health.