While a professional can always help, there are some common plumbing culprits you can check yourself to see if you can find the sewer gas smell. For example, you should check your water traps, sometimes called P-traps and S-traps, which are located under sink, shower, and laundry drains. The wax ring beneath the base of your toilet, which creates a watertight seal with the plumbing, could also have gone bad.

Homes built before the 1990s may contain asbestos, but the only way to be sure is to have your home tested. Hire an asbestos testing and removal service to determine whether you have the hazardous material in your home and the best process for removing or sealing it.

Asbestos is commonly found in certain older homes, depending on the time period in which they were built. Asbestos use in home construction began in the 1920s and peaked after World War II before being limited by legislation in the ’70s, so a house constructed in 1880 is unlikely to contain asbestos, while one built in 1950 is much more likely to. Research a home’s history to determine the time period when it was built and any renovations made since.

Depending on the size of your home, the inspection process could take a few hours or a few days. While inspecting your home, the asbestos specialist will take small sections of the potentially contaminated material. They will then send the sample to an accredited laboratory or the local health department for testing. 

The cost of asbestos testing depends on your location, the home's size, and the testing area's complexity. Plan to spend between $230 and $800 for testing. During testing and while handling potential asbestos, the specialist may wear protective gear, including gloves, overalls, appropriate footwear, and respiratory equipment.