The picture is the lower RH corner - removing the rear floor console and then the side panel trim will show that area in the picture.
You won't feel dampness in the carpet if it's leaking at that point. Your floor area below your floor console will fill up with washer fluid though, but there's a ledge between that area and the carpet in the 3rd row so it won't leak into there.
Take out the floor console - if yours is a standard length, there's two large plastic nuts to remove and then the console comes out (4 if it's an XL length). Then you'll see the underside and if any washer fluid is leaking into that area. To get access to the hose as shown in my picture you just need to remove the plastic trim around the 3rd row speaker, the tie-down for the cargo net + anchor and then you can pull the sidewall trim away from the cab and get to that hose.
