I'd remove the lower kick panels on the dash, get a big flash light and turn on the garden hose and run that mother while in the car until I found the leak.

Get a friend to help you....

I'd bet they f'd the windshield somehow if the leak didn't start until after the repair. I'm not even sure the passenger side has many gromets. I don't have my car at the house so I can't check. My older rides all leaked like this from the windshield washer bushings but I'm nor sure if this is an issue on our cars. Is the wiper motor in the cabin...if so it could be an issue then.