1994 Ford Escort Water damage

After an unusual rainstorm lasting 5 days, water leaked over the windshield, behind the dash, and down into the passenger foot well. The heater no longer works and the radio crackles. After checking the windshield was sealed with no cracks, I looked for worn hoses and found none. Is it possible, for the seals and firewall to have failed? If so, is this common due to the vehicles age, or could the water have overwhelmed the seals? How can I tell the difference between age and fluke accident? This LX wagon has been a goin concern. The only part replaced has been the waterpump in the 14 years since I bought it, and the mechanics say her compression is almost equal to when it was bought.