Im seeing water in my spare tire well. Why?

Clean, dirty? If clean probably the hatch seal is damaged somewhere or pinched. Up near the top. If dirty it could be damage to the wheel wells letting road spray in. Also check the antenna. If it leaks the water will end up in the hatch and the tire well is the lowest point.

Also possible you carried something in the back that had a little water in it (leaking water bottle?).

 

Jim- It is a potential concern for the EV batt you want to minimize the water.
A few owners have indeed mentioned this so if you search you will find. Unfort it can be hard to track down cause. Automated car washes one cause for some.

 

Yes reports of water in trunk. Some have been caused by a crack in the body seam located at the top of the hatch valley right off the hinges. In the valley itself in the top corners you'll see where the factory spot welded the quarter panel to the roof. You can see the spot welds under the paint. Reports of cracks right there. You have to take the inside covers off to expose and check for rust trails. Cracks probably from slamming the hatch all the time or maybe the car see's alot of really rough terrain and gets a beating.

Some have reported water coming in through a missing valance piece in the pass side rear wheelwell back feeding water in the battery area.

And some but few have reported a leaking seal in the taillight. You should see water tracks at the bottom of the seal inside.

 

I purchased a CRX with that problem. It took me forever to hunt down the culprits.

The big one was cracks in the body seams under/around the hatch area. I fixed those with silicone sealer.

The other problem was tail light gasket failure. I tried a number of different things, though never purchased new ones. I wound up simply drilling holes on the underside of the plastic to let out any water that may have gotten in. It worked for me on my $875 CRX, but I wouldn't recommend drilling holes for you. Not yet anyway...

 

in the meantime remove the rubber drain plugs in the spare tire well and 12V battery compartment (yep that is PIA you have to remove the battery).

check the rear footwell carpet for dampness, if its damp you may have to lift the rear seat bottom at the front to release the rear carpet, then remove the rear door sill plastic covers to remove the rear carpets, you may not have to remove the carpet entirely as that entails removing the front seats, GPS & JBL units, I bungee corded my rear carpet up to allow some air circulation in to dry the carpets, there are also some rubber drain plugs in the rear seat footwells under the padding (toyota calls these sound insulators)

some threads say the best way to diagnose is to sit in the car while someone outside sprays it with a garden hose until you find the problem, which is very difficult to do, the crack could be tiny and the water had been slowly accumulating for years.

 

Yes - gee thanks Toyota - I'll sit in the hatch while a buddy hoses down the car rather than you sell a car that doesnt leak. Awesome. Next time I'll buy 2!
Also you can puch the rubber stopper up from under the car if you dont want to take the battery out. Might save some time..

 

i haven't seen it on my '04, '08, or '12, must just be lucky i guess. the worst thing is that these problems are happening on cars that are only 7 or 8 years old!

 

Others have experienced more; water spilling onto floorboards.

Look at this link. Maybe you have the same cracks? You can troubleshoot and repair the same or a better way.
Water filling driver side floor pan. | PriusChat

 

I own 3 2011
All accumulate water under 12v battery... there’s a rubber plug..bung... I pulled them all and they stay dry now .also check under spare...