As mentioned, sewer gas will leak into the home for different reasons, one common reason is dried out plumbing fixtures. An example of this is the plumbing trap which is designed with a water barrier to prevent sewer gas coming back into the home, if this dries out, there is no barrier to stop the gas from entering the home. You are more likely to experience this during periods of dry weather or in bathrooms that are not used very often.
Some other reasons for sewer gas leaking into the home are cracks which form in plumbing drains, ventilation pipes or foundations. On occasion, plumbing vents are positioned too close to the home's air intakes which is another way sewer gas can enter the house. Another simple reason you may smell sewer gas is airflow around the property.
Why is it so important to find out the reason that sewer gas is leaking into the house? Whatever the reason is for sewer gas to be leaking into your home, it’s important that you have the problem checked out by someone qualified who will be able to identify the cause of the leak. Sewer gas can be a dangerous problem and could lead to sulfide poisoning, asphyxiation, due to sewer gases displacing the oxygen in the house, or even risk of explosion and fire.