Windshield washer reservoir bottle leaking

[Dave2001S]

Thanks Woodsman, are you referring to the plastic 'L' shaped fill tube or a different line? The fill tube seems to be connected to a box or perhaps its the side of the reservoir bottle itself, I can't tell because the main part of it is apparently installed inside the wheel well and isn't viewable unless one removes the lining of the wheel well.

While we are on the subject of washer fluid, do you guys put any window cleaning fluid (such as windex or the like) in your washer? Or just plain water?