Before diving into the windshield seal make sure the water is actually coming from around the glass. Many times the seal around the hood release or cruise control will allow water to enter the car mimicking a leaking windshield.

Pull the knee bolster out and the carpet down and have a helper spray water under the hood around the seals on the cruise hose or hood release. Actually spray water everywhere in that area but NOT on or around the windshield. With a flashlight and the accompanying contortions necessary to watch the back side of the firewall you might get lucky and fine your leak.

Mine was the cruise control vaccum hose and some silicone caulk applied to it sealed things up.

Randy