On our slides (not Monaco) there are little plastic cups flush with the floor. These are at the junction of the floor and the slide opening. These are meant to catch any water rolling down the seals or sidewall of the slide. During the manufacturing the carpet had fibers that were dipping down into these bowls. During heavy rains the water would wick up the carpet fibers and spread out. It was amazing how mach water came in. The carpet would be sopping wet for about a foot away from the bowls.
To fix the problem I cut back the carpet so it no longer dipped into the bowls. This stopped the problem.
Another leak was due to old window sealant where the window met the outside wall of the RV. The sealant had a series of gaps no more than a half inch long at the top of the window. The water would follow the frame of the window down and then drip down one of the wall studs and flow out under the inside wall panel and get the carpet wet. Again the carpet would be sopping wet and extend out over a foot from the wall. This would only happen during heavy rains and with wind blowing towards the window.
It's amazing how much water seems to get in from tiny gaps.