Sewage Smells in a Slab House

Sewer Gas

Sewer gas is the common name for a mixture of gases produced naturally when sewage breaks down inside your household plumbing system. Sewer gas is mostly hydrogen sulfide, a sulfur compound that has a distinct rotten egg odor, but it also contains smaller concentrations of ammonia, methane, carbon dioxide, sulfur dioxide and nitrous oxide. Depending on how contaminated your water may be, sewer gas could also contain chlorine bleaches, industrial solvents and gasoline.

The first step in addressing the problem of sewer gas outside your home is to follow the rotten egg odor to verify the actual source of the gas. Check the plumbing connections around your slab foundation. If your home uses a septic system, check the septic access vents and the septic drain field to see if the smell is stronger there. Wherever the rotten egg odor is the strongest is likely to source of the gas leak.

Have a plumber repair the sewer gas leak right away. Some common causes for sewer gas escaping from a home include a full septic tank that has not been emptied as often as necessary, clogged drains or a plugged roof plumbing vent. Unless you are highly experienced with plumbing and sewage systems, a professional should always handle these types of repairs, both because of the chances of damaging your plumbing further and because of the potential for health risks associated with sewer gas exposure.

Since sewer gas has such a strong odor at even low concentrations, humans generally are aware of the presence of sewer gas before they can be exposed to a dangerous amount of it. But if concentrations are high enough, sewer gas exposure can cause eye irritation, labored breathing, nervousness, dizziness, nausea, headache and drowsiness; exposure symptoms become more serious the higher the concentration of sewer gas. Prevent people or pets from frequenting the area around the sewer gas until repairs are completed and there is no longer a rotten egg odor.