2007 hatchback 1.5: Puddle in rear driver-side footwell

Hey everyone,

This morning I drove my 2007 Prius for the first time in 16 days. I drove it for about an hour.

When I got home, I saw this in the rear driver-side (right-hand) footwell:





It was not raining while I was driving. I keep the car parked on the street, and my region has had the rainiest September in recorded history, and we have had multiple yellow alerts for rain in the past week.

It's possible that the puddle was there when I set out, and I just didn't see it. I throw my handbag back there while I'm driving, and I only noticed it when I went to pick up the bag. That is also how I know the puddle was not there the last time I drove the car.

I called up a body shop that I trust. They previously have saved me from puddles in the passenger footwell by noticing that a plug was missing, so I thought they might be able to help this time. But they said it was beyond their expertise.

I called up my usual garage and will take it to them tomorrow. However, they don't specialize in this kind of thing. So I thought I should ask here. I see that some people have had comparable experiences, but without any definitive answers that I could find.

Has anyone experienced something like this? Did you find the source of the leak?

 

Thanks so much @dolj, that is exactly what I was looking for, but I was using different keywords.

 

Update: the mechanic tried sitting in the car while someone hosed it. No water came in. He couldn't find anything on visual inspection either.

So he basically told me he couldn't reproduce the fault and he doesn't know what the problem is.

His advice was to, first, take it to a car wash/detailing place and get them to clean and dry it. Then "keep an eye on it" and take it to a specialist body shop if it happens again. And was I sure I hadn't left that window open. (Yes. I don't open that window, therefore I can't have left it open.)

I will take it to be cleaned tomorrow morning, but first I'm going to try the "dollar bill test" described in this thread: Water only in the back floor | PriusChat That's a case that sounds very similar to my current problem, and I'm hoping that this assertion proves true: "Aside from the door frame seals, there is really no way for water to get onto the rear seat floor, except an open window."

 

Update: I took it to a specialist body shop. It took them a week to find it, and seven hours to repair and reassemble once they found it.

The battery, spare tire area, and the back seat were basically waist deep in stagnant water, which ran through channels via gaps in the rear hatch door seal.

The body shop were not able to find the leak by the usual methods, e.g. hosing the car from the outside. If we hadn't had an unprecedented month of heavy rain causing the puddle to form in the rear footwell, I would never have even known there was a leak.

To find the source of the leak, they had to dismantle most of the back of the car, including the back seat. To fix the leak, they had to dismantle even more of it. There are some visible spots in the rear hatch door area where they applied sealant, but I won't post pictures because, for anyone experiencing a similar problem, just applying sealant to those spots would not be enough to solve it.