I want to install a basement sink. The sink drain will be below the sewer pipe. By code can I drain the sink into the sump and then let the sump pump pump the water to the sewer or do I need a second under sink pump ?:confused:

You're going to have to comtact your local Building Department to find out if that's acceptable. Im my area it would be against code to let smelly gray water accumulate in a open sump in your basement. Good luck, Tom