97_water leaking into driver's side

Water is leaking into the driver's side floor board area. I've had the windshield sealed properly - but when I wash it with a hose or when it sits outside with heavy rains, the water leaks in and soaks the carpeting on the driver's side. It appears to be coming from behind the dash - it's not from a window. Any ideas on the source of the problem? Thank you.

Look at the firewall from the engine side. See if you can see anything missing - like a small, round rubber grommett. These can come loose and allow water in the cab. It helps if you put a bright light under the dash in the cab and then look from the engine side. See if you see any light.

Thank you very much. I will into it this weekend. I appreciate the help!