Homeowners should be aware that connecting sump pumps to the sanitary sewer is illegal, plus it can cause big problems!
Sump pumps are designed to pump groundwater and rainwater, while sanitary sewer pipes are meant to carry sewage only.
Sanitary sewer pipes under the street are typically only eight inches in diameter. Often, the pipe slope is not very steep, which is common in most sewer collection systems. There is only so much sewage water that can flow through the pipe, and if more sewage enters it, the sewage will back up and start filling the sewer laterals that run from homes to the sewer main. When more sewage or water flows into the pipe, it will back up even farther, eventually pushing back into someone’s basement. As a result, the sewage might come out of a neighbor’s basement toilet or washing machine drain.
Sump pumps should discharge only into the yard or storm sewer – not to the sanitary sewer. Remember: It is illegal to connect your sump pump into a sanitary pipe!