With a helper go to a car wash. Spray around the door and windshield with the helper inside to see where the water is coming from. This is the easiest way to find the leaks and plug or repair them.
The door has drains in the bottom to allow rain water to drain out, perhaps the drains are plugged up with debris and the door has water collected.
Could be the heater core leaking Could be a bad windshield or door seal Don't forget a possible plugged A/C drain plug. Does this happen when running your a/c?? If you have a sun-roof, the drains could be plugged. If so, they will leak in bad weather, causing water to run down the passenger door post. If the rain is hard enough, it will soak the passenger floor mats. I took mine in to Toyota and asked them to clean the drains (because I could not find a post telling me where they are located).
My guess would be the cowl drains are plugged up with debris. Remove the wiper arm assemblies and the cowl panels/screens and clean out the drains.
If it is clear rain water, the drains in the cowl vents are probably plugged up with debris. If it is engine coolant and it is only on the passenger side, the heater core is probably leaking.
Are you asking about and indirect waste?
If it's leaking the moonroof drains near the front are plugged.
The drain is plugged somewhat between the upstairs and downstairs. Need to snake the drains.
Sunroof drains are clogged.
The sink drain is plugged,or you have the dishwasher hose hooked up in wrong place.
1985 720 pick up a/c drains on passenger floor
On either side of the car (under the doors and rocker panels) there is a place where the body parts come together. That is where the drains are for the quarter panels. If for some reason they have been bent over (they hang down about 1") they won't drain. Straighten any bent areas. This should take care of the water collecting in the quarter panels and flowing into the passenger compartment of your car.
If you have a sunroof, there are drains that go down the side - they get plugged up and need to be cleaned - at least that what happened to mine.