When we purchased our coach, the kitchen slide would leak when out.
Tried putting one of those rain gutters above it that stick on, that helped some, but didn't stop it completely.
Ours has the slide that has the arms that are attached to the coach opening and go to the bottom corners of the slide. After several tries by the dealer to find out how the water was running into the coach from the rear bottom inside corner, I finally found out myself.
The pin that the arm attaches to on the bottom of the slide goes into the bottom main frame of the slide. The water was running down the outside of the slide to that pin and followed it into the main bottom frame, which is hollow, then the water was running in the frame to the inside corner and out onto the hardwood floor.
I had the dealer remove the arms and seal the pin in the slide and frame. NO more leaks since.
Since the passenger side bedroom slide has the same arm assembly, I had the dealer do it also as a precaution against future problems.
That was the only leak we had, except the one that I caused when I didn't tighten the ice maker fitting and water leaked under the refrigerator and into the cabinet below the frig.
But that won't happen again either since I sealed the outside frame on the frig so that water can't get under it and must run out the access door, just in case some dummy forgets to tighten the icemaker supply line after dewinterizing AGAIN!