Thor 33sw Water Leak in Storage Compartment

In my case, it's the door seals they're cheap & they suck, going to replace them.

Mine leaked too, until I ran a bead of silicon all around the point of contact of the basement attachment points and I ran another bead on the inside - no more leak. In rain the tires threw the water right up to the underside of your motorhome right where the basement units are attached. They have foam, but it's a hit or miss, and usually a miss with the foam being in the right place when they attach them. Mine have been that way for a year now and no leaks. I drive to Washington a lot from California, so lots of rain.

The unit leaks in the rain when it is parked or when I spray water above the compartment but not on to the compartment. I have put additional moulding all around the door but water still gets in.

Is this a leak from above (i.e. when parked in the rain) or from underneath (when driving in the rain)?

I need to go around and reseal mine from underneath. I don't know if they have always been a little leaky, or if it's simply that the 17 year old sealant etc. is rather past its prime. I kind of suspect the latter. It looks to me like a little bit of surface prep and some quality time with a caulking gun would go a long ways to improving things.

You may need to put additional rubber seal around door edge. To stop water leaks I had to put an additional layer of rubber (not foam) around door seals.

I have had storage compartment leaks that occurred when driving in rain. The compartments are supposed to be sealed, but several of mine were not (35SK).