Sewer gas can enter a home through a floor drain, from a leaking or blocked plumbing roof vent, or (if the gases are in soil adjacent to the house) through cracks in foundations. Sanitary and farm workers can be exposed to sewer gas during the cleaning and maintenance of municipal sewers, manure storage tanks, and home septic tanks.
Flush floor and sink drains with water to prevent the traps in pipes to the sewer from drying out.
Occasionally check the roof plumbing vent for blockage from debris such as leaves or bird nests.
Never enter a municipal sewer line, manure-storage tank or any other large storage tank without proper training and equipment.
First, following the odor, try to locate the point of entry, such as a basement floor drain. Check for a blocked rooftop plumbing gas vent. By adding water to the floor drain or removing debris from a roof plumbing stack vent, you may be able to prevent sewer gas from entering your home. In the unlikely event that a leak in gas vent plumbing is behind walls, a plumber may be needed to find and fix it. Some local public health departments may be able to offer home inspections.
Symptoms of headache, nausea, dizziness, or drowsiness may indicate exposure to an odorless gas like methane or carbon monoxide, or to hydrogen sulfide, which smells of rotten eggs. Anyone experiencing severe symptoms should seek immediate medical care.
If you suspect that high concentrations of sewer gas have accumulated in an enclosed space, you should evacuate the area and contact the fire department for assistance. Avoid creating an ignition source such a spark from an electrical appliance, match, or cigarette lighter.