Water dripping through firewall behind the dash

A few more places to check if it still leaks. Make sure there is a foam seal between the hole in the firewall and the plate around the steering column, where the column goes thru the firewall. You should be able to see it best from the engine compartment side. Also, look in the door jambs, right above where the door hinges bolt to the jamb, you will see the seam where the upper and lower cowl joins. There should be drain holes in those seams, to allow water to run out of the cowl. If those holes are stopped up, it could cause the water to pond up and find a way out elsewhere. A coat hanger, shop vac and an air hose with a blow nozzle on it can get a lot of junk out of a cowl. Good luck to you. Cary traffic is bad enough without water drippin on your feet!