Drain filter on front.

Thanks for the question. It's normal for water to come out of the debris filter when it's opened, and it could be a significant amount if you don't first use the drain hose located next to the filter to empty most of the water into a container. I would suggest reviewing the instructions on page 26 of the WF350 user manual which shows how to drain the water using the hose prior to opening the debris filter for cleaning. - Ms. Samsung