hello mate, not sure what car you have, but, i've just had major problems with my Passat getting soaked in near side (passenger side) footwells (front and rear)caused by a water leak at the pollen filter housing situated on te bulk head. It's a common fault where the rubber seal deteriorates, on the Passat which VW stealers are aware of and will fix under warranty. May be simillar on other cars, worth a try? Good luck and best regards
Paul