I walked in to the laundry room to grab a beer from the "Magic Fridge" while making dinner and spotted water on the floor. Moved the washer and unscrewed the drywall to take a peek and noticed the small patch just to the left of the washer. Moved the washer again and felt underneath that corner. Yep, it's wet under there. I did pull the drywall just to be sure it wasn't something in the wall. Nope. Everything is still as dry as a bone so I shut off the washer supplies and will investigate further tomorrow after work.

** UPDATE ** Turned out the washer fill valve had a bad o-ring. 20 mins and less than a nickel to fix it.