Turn off your sump pump and unplug it.
Wipe and clean off the end of your existing sump pump outflow pipe with an old rag. Remove any dirt or grime and dry it off thoroughly.
Swab the end of your outflow pipe with polyvinyl chloride (PVC) glue and attach a female PVC connector end to it.
Clean one end of the new PVC pipe that you are going to use as an extension drain pipe. Apply PVC glue to one end and attach a male PVC connector end.
Apply PVC glue to the male end of the drain pipe and then connect that male end to the female connector you just attached to the existing outflow pipe.
Allow 1 to 2 hours for the freshly glued connection to dry before plugging in your sump pump and turning it back on.