We have water directly under the front passenger seat. No water in the footwell. All door gaskets are fine, and the plug in rear passenger footwell is tight. In order to determine where the water comes from, we have to take the seat out. We found we could remove 3 floor bolts, but not the fourth. Is there any way just to flip the seat up without taking the car apart?

Lower should unbolt and turn upward and out. Then unbolt rear ( back ) of seat. Might require a slight upward push to remove.

We must have received part of your e-mail. It starts with "lower should unbolt"... which we do not understand.