Perforrated floorpan? Get underneath and give the floor a GENTLE poke/prod just above the cataclysmic converter (now named because it converts heat and salt water into rust).
Don't know about your Mk. of Jeep, but as the XJ is a famous rust bucket, I suspect they are all quite suseptable once the underbody protection is compromised
OR:
Take the carpet out and hang it in the garage, face it, you got to dry it anyway!
Mop up any puddles and dry everything as well as you can.
Sprinkle some chalk dust on the firewall and in the footwells, try to avoid perfumed talk unless its the wifes car.
Then climb inside and get someone to spray water vigorously round the windows, gutters, doors, wheel-arches etc.
Hopefully a little river will start to flow, follow to the source as it were and plug the hole as required.
Re-mount the drivers seat and use the car while you fix the laek and the carpet dries out, and dont forget to repaint any new metal work/welding done or you'll be doing this all again next year!
Oh, and welcome to the club!
