Rain water leaking into cabin

If your car has a sunroof there will be a drain on every corner. The front hoses run down the A-pillar, the rear hoses down the c-pillar. Water can run down the A-pillar to the floor if clogged. If you don't have a sunroof the drain for the heater box is on the passenger side if I recall correctly. This can be clogged or simply fall off, to check, Spray some water down the cowl. If not that, spray the edge of the windshield (top, side and bottom) and if by some chance you still cannot locate a leak make sure the grommets for the wiring in the firewall are in place. Those are my best guesses. I hope it's an easy fix. Best of luck.