Have you used your air conditioning lately? The most common reason for water to appear to be leaking on the passenger floorboard is that the condensation drain for the air conditioning is plugged. Unfortunately, the drain is pretty much inaccessible to the average person and I have yet to discover a reasonable method of clearing it other than paying the dealer or a mechanic to do it.
The other, less common causes for that type of leak is that the heater core is leaking, in which case the fluid will be antifreeze rather than water, or the door seal on the passenger door may be leaking, or the windshield gasket may be leaking.
heater core is leaking.
Check AC drain and clear the blockage. Also look for firewall sealer skips.
your heater core is leaking. Needs to be replaced
There is no drain plug but a condensation drain tube located on the passenger side firewall or just below ( rubber tube sticking out ) It may be plugged and a coat hanger or compressed air will open it. Your heater core may also be leaking if there is also coolant on the floorboard. If so it will need to be replaced.
Only when it is leaking.
If you mean leaking water in the car then the drain is probably stopped up.
Sounds like a heater core is leaking. That is a very common problem. You will be far better off to have both the heater core and the AC evap replaced at the same time. they are both in the dash and they both commonly go bad. fix both with the same labor.
rear main seal leaking
Lower passenger side of firewall.
Rear passenger side.
2009
Leaking injector is the most common cause.