Water leaking on to floor front passenger side

I own a 2002 Hyundai Elantra which has developed a mysterious leak allowing water to come into the front passenger side floor when it rains. Not all rain storms result in water inside which is another mystery. The gasket on the right front passenger door was replaced but the leaking continued. I have had to rip up the carpet from the floor due to severe mold situation.

What I do know is that:

The water is not coming from under the dash as that carpet and foam area are never wet. It is not coming up from under the car because driving in a rain storm does not result in a wet floor. It is not coming in the side window as the door panel is never wet.

Do you think it might be coming from a plugged cowl drain which was mentioned by someone?

Also how does one remove the cowl to clean out dirt/leaves?

Is this a job that someone who is not a mechanic can do?

Thank you for your time and assistance

The drain tube for the HVAC system might be partially clogged. This will cause exactly the symptoms you describe. If condensation from the AC evaporator, or water from a rain storm, overwhelms the drain tube’s ability to carry it away, the water will drip onto the carpet instead of onto the road.

The drain tube is on the firewall, low on the passenger side. You’d probably have to raise the car to see or reach it. This is probably the “cowl drain” that was suggested to you.

A clogged sunroof drain tube is another possibility.

It might be from the cover of the cabin air filter, sometimes these leak.