2003 Buick Regal Water leaking in car

I recently had the lower intake gaskets and valve covers replaced to correct oil leaks. Last weekend, we had severe thunderstorms and I went out to the car and there was standing water on the floor. The water was only located on the front passenger side, not driver side. No window was open, we don't have a sunroof, the seat wasn't wet; it was just soaked on the floor. Would there be any reason for the recent engine work I've had done to cause this water leaking. This has never happened before and I am not sure how much I trust the place that I took this car too. Thanks!