Place a plunger over the floor drain in your basement to cover and block the drain.
Locate the catch basin in your home. It is likely in the basement connected to either the basement sink or washer faucet.
Fill the basin to the brim with water and soap. Use a hose to fill the basin. Allow the soapy water to sit for about a half an hour to soak the piping.
Remove the plunger and the water will drain, clearing the pipe.