I have an 08 plate C max and as in an earlier post I have experienced both passenger and driver foot wells sodding wet, when lifting the mats there is a hole in the carpet you can put a finger through and there have been puddles of water. I have recently discovered an issue which I hope will resolve this problem, I do still hear water swishing inside the car when I am turning sharp corners but I hope this will disappear once the remaining water has founds it's way out. The problem I discovered was at the bottom of the front windscreen where the windscreen meets the plastic scuttle, there was a gap, the two had become parted, this easily allowing water to enter into the area below, after further investigation by removing the plastic scuttle which I noticed did not align correctly with the holes for the windscreen wipers, I discovered a water marked area on the plastic below, following the mark it lead to an access hole in the corner of the car above the passenger arch for electric cables. My conclusion was the water was running down this hole and entering into the foot wells of the car. There is an adjustment which can be made to hold the scuttle in place which keeps it tight to the window, I have also now applied sealant along the bottom of the windscreen where it meets the scuttle in hope that this solves the problem, I have only done this in the last couple of weeks so I will let you know if this solves this frustrating problem!