Sewer laterals, which connect a home’s plumbing system to the municipal underground sewer system, should be regularly maintained. Over time, cracks in sewer laterals can emerge from tree roots and shifting soil. Cracks can allow groundwater into your lateral, which can increase stress on the municipal sanitary sewer system, thereby increasing the chances of sewer backup. As well, loose joints where laterals are connected to home plumbing or the municipal sewer system can increase the risk of sewer backup.

Over time, the sanitary sewer lateral may also become clogged with fats, oils and grease (FOGS) or other debris, which can restrict flows and cause sewer backup (see Option 5). This may especially be a problem in older homes when the lateral has not been routinely maintained. Sewer laterals are accessed through the cleanout port, which may be located either inside of the basement or outside of the home, close to where the lateral enters the home.

To find out how well your sanitary sewer lateral has been maintained, you should talk to a licensed plumber who can carry out an assessment of your lateral.