Leaky water valve.
In homes and businesses there are high chances of water damage because of all the pipes that run through the walls. In this home the shut off valve behind the appliance was leaking and caused water damage that went unnoticed for awhile and turned into mold. Always check your appliances for leaks every once in a while so mold doesn't have a chance to grow. If you find a leak and call SERVPRO right away there's a good chance you can avoid mold from growing in your home. Don't wait call SERVPRO of NE San Diego if you have water damage in your home!