Water in your basement is always troubling. You aren't sure where it came from, sometimes you don't know when it started, and you don't know what to do first. The one thing you do know for sure is that you want it gone. First things first, take a few photos of the damage and where you think it might have started, you can show these to the plumber, basement waterproofer and maybe your insurance agent later. Then it's okay to clean up the mess. You want that water out of your space before it does more damage and/or cultivates mold. Next, determine the source as best you can. If it comes through a crack, from the cover joint, where the wall and floor meet, along a basement wall or up from the floor, call a waterproofer. If it comes from behind a washing machine, hot water tank, around a sump pump, or from a pipe (even one in a basement wall) you probably want to start with a plumber. Once you have a professional's opinion your mind will be at ease and your problem on it's way to being addressed.