What would cause water only when raining to come up through floor?

Hello Norma, It sounds like you have a hole somewhere. Start on top of the trailer and try to find it. It will need to be patched. Water always finds the path of least resistance. I think the water is travelling from the hole and down inside your wall. Where the water pools is probably the lowest point in your floor. I recommend finding that hole ASAP. Before your flooring buckles and you will have two problems to fix. Good luck.

Up through floor in? Can you repost your question please?

Poor drainage around your foundation is my first thought. I'd suggest taking care of that professionally if you can afford it. Then apply Drylock to your floors and walls downstairs. Be sure to get multiple quotes, check references, licenses and liability. Best of luck.

You need an inspection. My best guess is the slope of the land sends the excess water towards your home instead of away from it. Over time this can cause a lot of damage and get quite expensive. The sooner you fix the cheaper it will be.

Hello again. I don't mind writing back at all. Like I said, that's where I would start. It's hard to say where the hole is without looking for it. Best of luck.

I'm in Florida too, 70's prefab, up off the ground. It sounds like there's a leak coming from the roof finding its way to your bathroom floor. Water will flow down first then level out. Check for roof leaks. Leaking windows? Proper installation of gutters? Caulking may be all you need. However, your subfloor may have been compromised and should be replaced once the leak has been corrected. Best of luck.