Water dripping from underbelly on Montana HC

[Dorrie]

Sorry everyone for asking another question. Maybe someone had same issue and we can go from there...
Starting Monday found a fist size wet spot under the camper. Hubby opened underbelly ( about a foot before steps, directly in the middle) about cup of fresh water came out. Saying fresh meaning not from black tank. Ok, left it open to dry and did the process elimination. Ran water from every spigot and flush. Filled the tanks up, nothing. Had a good rain last night. Wet spot bigger. Looks like a leak because of rain. We searched all over inside for signs of rain leaking in, nope. All dry inside by slideouts too. Hubby will check roof when gets home. So any ideas where he should start first. Let me say he is a big boy and he is nervous to be on it. (6'3" 288lbs) so any ideas will be appreciated.

[JRTJH]

Check the exterior of the rear wall, where the FILON meets the bottom coroplast. Many times there is a "DARCO wrapped fold" that is stapled to the bottom of the rear wall braces. Sometimes water will run down the rear wall, hit the bottom molding and instead of running off the wall, it will wick under the bottom and seep into the coroplast. It never gets "inside the trailer" and isn't exposed to any of the structure, it's just "there".... Sometimes, you can add some screws with washers to pull the DARCO up so water doesn't run down it. Other times, just raising the front of the trailer an inch will stop the wicking.

Sort of like holding a water hose in your hand, some water leaks down the nozzle, drips onto your fingers and before you notice it, your shirt sleeve is wet. Your elbow is always safe, so no real problem, just a "part of using the hose"....