My car floors are very wey I've dried them out a few times. When it rains the get wet. The front seams wose bu it get to the rear footwell and after not using it this weekend at all it's wet again but it has rained heavily.  Thanks in anticipation. 

Door or boot seals?
Possibly a missing floor grommet somewhere.
Rent a fogger and look for smoke coming out of seals or panel gaps.

Sent from my SM-G965F using Tapatalk

It was dry not driven but it rained . It seems to be coming in through the front. Could it be the trim over the wipers the  is a gap

Has it ever had a new windscreen fitted, it could be the windscreen seal. When did you first notice it,  was it after you had some work done or has it come on gradually.

My 2019 focus has just been in because the widescreen spilt from the body, the carpets weren't just damp there was a puddle it was coming in that fast.

I had the same issue with wet carpet on passenger front footwell in my Fusion. If you take off the plastic trim in front of the windscreen, you’ll see there’s an area below it full of water. theres a drain hole in the centre (if I recall correctly) which you might not be able to see because of the water, soak up water till you can see the lowest point, this is where the drain hole is. It will be full of silt, mine also had berries from the tree I used to park under in it. Poke something long and thin down there, a piece of thin threaded bar might work or a kebab skewer. I did mine when it still had some water left in and once I poked it I saw all the water disappear. Problem solved. This is a common problem on many cars so I’ve come to realise. I also did the same thing to a Passat estate with the same problem. Hope this helps others to resolve the problem too. Enjoy 🙂