Urgen- Ford Mondeo Water Problem

Inside floor and rear seats are getting continually wet (sodden you could say). Have tried water hose test in car wash but no sign of water getting in. In summer time when heater was not used problem didn't seem to arise but now since I have started using the heater again for winter the floor is once again continually wet and the car seems to be going through a lot more water. Have had the car in a garage to be checked out but couldn't find the problem. ANY IDEAS OUT THERE?????:banghead:

Simple. Your heater core has sprung a leak and its leaking water from the engine on the floor. You need to replace the heater core and find a new garage. If they didn't pick up on that, they don't deserve to turn a wrench.