Water in passenger side...back seat more than front at foot rest.......

[Love my 83 300D]

Hey guys,

Any ideas as to why after every rain or snow that I get puddles in the foot rest of the passenger side back seat and less in the front?

Just bought the car and spoke to guy on the phone at a parts place that said there maybe some drainage holes clogged from under the hood..... does it sound familiar? Where are these drainage devices if it does sound correct.

Any other ideas as to what it could be?

All responses appreciated.