Water leak issue.

very common. it's usually a seam weld between panels, or the hatch hinge points. one guy did have a broken rear windscreen washer line though.

 

Got a similar issue with mine but haven't had it around to troubleshoot it (daughter has it at school). My leak doesn't appear to be quite as bad. Looked at the body seams but haven't identified it yet. I do know that the rubber on the rear hatchback switch is compromised and I suspect water may be ingressing there. My other suspicion is the wheelwell vents as they were damp when I inspected them. Plan to fix the switch at the next opportunity and monitor for further water accumulation.

OP, search for "leak" and you should find the threads that Bisco referenced above.

 

Did you perform a search before posting? Searching "water spare," pulls up a lot of other threads with the same issue (water infiltration).

Read the following thread in its entirety! If you do so, you will be able to duplicate the steps OP performed, and most likely find where the water is entering the car.
http://priuschat.com/threads/water-filling-driver-side-floor-pan.140242/#axzz3PRRj7bmR

If the car had ever been in an accident, perhaps poor body repair?

Don't forget to check for possible water leakage via the tail light assembly (brake light/parking light/reverse light)

 

Yep u probably have a body seam leak.
Right next to the hatch hinges in the corner valley you will see where the quarter panel meets the roof and the seam is not painted over .
It may be a crack also that travels from there to under the black plastic trim piece that covers the roof valley. That just pops off.
In the meantime take out the black rubber plugs under the spare tire so the water can drain out.

 

They just pull off...if you have some nylon prying tools, it may help.

 

yes those black strips pop right off. Trying to picture if its easier to open the hatch revealing the end edge and its easier to lift up the edge but my car is not here right now. Good time to wash the car and wash that valley out after you remove them. Those strips are like $100 at the dealer btw. I need some just cant see spending $200 on those strips at the moment because they dont look new.

Dealer sells plastic conditioner called Back to Black that works well. Red bottle. hard to find in auto parts store.

 

Hi I have the same issue now Sciencekit! Mine is the result of bad body work. I had my windshield and roof replaced after a tree branch smashed them. My questions to you are: didn't your car stink ? and did you ever manage to solve the problem? does a water leak ever truly get resolved or is it basically a matter of time before the car is totally sabotaged?

 

no, you usually can't smell the water sitting in the 12v battery area. yes, people have had success repairing the seam and hinge leaks. it sounds like you need to have a talk with your insurance company and body shoppe.

 

I know this is an older thread, but I had a 2008 Touring leak in area not mentioned...where the rear spoiler mounts to the body. Of the 4 bolts, one was very loose, one less so and two just needed to be snugged up a bit. Since I did that, zero water intrusion after 2 storms and 5 minutes of blasting the car with a garden hose. Note: the interior trim piece covering this area just pulls off and snaps back in...no screws, etc.