2001 Lexus rx300 water leak on driver side

You're windshield, door, or window seals are leaking.

I am having the same problem with my 2006 350rx. I have found that somehow the drain tube are draining into the inside of the cab and not out of the bottom of the car. when I pure water into the drain holes it goes down to drain tube and onto the floor

I had the same issue. The front passenger side floor was wet after it rained. I read threads and watched youtube videos. It turns out that the drain tube was disconnected at the sunroof drain. The roof liner is somewhat impermeable so the water was running inside the roof liner down the plastic trim and onto the carpet. I pulled the roof liner back and put on a new hose clamp.