A:Answer Hi, Not sure about the latch, but its possibly the handle on top of the dirty water tank. I noticed that water will leach out the bottom if you leave water in the clean water tank when machine is not in use. For best results, empty and rinse out both tanks and let them air dry over night. I put the clean water tank in its place but leave the lid off, and just set the dirty water tank to the side until it dries out. This helps keep it new, and helps prevent mildew etc. in the system, and will not leak. Hope this helps.