Nissan Altima 2018

Leaking water into the car. Now that the A/C is being used, the passenger side front and back is soaked with water. What could the reasons be? Could it be as easy as changing the cabin filter? I did that last summer when it had done this for the 1st time and it worked. Afterwards it seemed off that no water was draining out underneath the car. I can be neglectful, I didn't end up bringing it to be looked at.