It's been raining in Arkansas for the past week and I just found that my 2017 Prius Three had some kind of water leak under the rear seat cushion. Both sides have the water leakage near the outside seatbelt anchor area. It was kinda wet under the seat belt/black steel anchor (I didn't open the rear door, windows were closed). It's weekend right now so I cannot take it to a body shop or a dealer, just trying to see what may be causing this issue. I tried to clean the wet part by the steel anchor, and I found debris and a wet leaf. I am thinking that my car is lacking some part that blocks water and debris from getting into my rear seat. Rear floorboard doesn't seem to be wet. I checked the C pillars, rear windows, window seals and etc., all seemed to be fine, couldn't find the leakage . No sunroof, rear seat didn't carry water or anything. Pictures included here.
Problem fixed by the dealer, had some waterproof treatment under the spoiler and some silicone fixed the problem. The car had an accident in 2017 and whoever fixed it half-assed on everything. But right now it shouldn't leak for a few years.
