I have a 2013 Abarth Cabrio that has taken to leaking. During rain the driver's side floorboard near the door/foot rest leaks. It leaks so much that a towel is sopping, and I can wring it out. The bad part, is that it doesn't leak that much each time. It varies.

My husband, who is very handy and technical has tried hosing it near the door and we cannot find any leaks. The seals all look and behave well (from what we can see). The roof isn't wet when I touch it, so I don't think it is the soft top, but it may be somewhere in the post near the windshield, or something else.

Help! I'm stumped! We live in the Washington, DC area of USA.

Check the weather seal that goes on the inside of the car where the door seals against it. My BMW Touring used to leak soaking the rear carpets every time it rained, I found that the seal was letting by as it met the roof and water was tracking through behind the seal, eventually running along the seal and into the car via capillary action.

Albeit unlikely, it's also worth seeing if the door window rubber is letting by allowing water to run into the door cavity and then onto the floor via any holes.

Is it possible that it's coming through the ventilation system perhaps the drains have got clogged with leaves? just a thought.

This stuff or similar...

http://www.ringautomotive.com/uk/products/Workshop+Tools/Leak+Detection/Fluorescent+Dyes/RLD3

you need a UV/black light torch but it is utterly invaluable for finding leaks, dilute the fluid, soak the affected area and shine the light on, any where that's leaking glows...

takes all the guess work out and therefore saves a load of time and limits potential damage.

Check it in the dark far easier to see

darkness isn't really necessary in my experience, this stuff glows really bright even if it is just a few drips

Isn't there an issue with the rear bumper seals?
Isn't there a thread on here all about it?

Something about rain coming in through the rear bumper and tracking along the chassis internals and coming out in the footwells.

Found it!
https://www.fiatforum.com/500/437858-front-passenger-side-footwell-wet.html
https://www.fiatforum.com/500/353579-water-o-s-front-foot-well.html
https://www.fiatforum.com/500/433846-leak-smelly-fiat-500-a.html
Maybe one of these is your problem?

Regards,
Mick.