The water in the foot area is likely from the front windshield rubber leaking. They are bad about that as they shrink over the years and seem to pull away from the top first. This is really bad when the leak is on the drivers side and there is a strong rain storm since the water can leak down into the horn button and short out the horn, causing it to start blowing.

Then you get to run out and disconnect your battery in a pouring down rain storm!

The leak in the trunk usually comes from the taillight gaskets drying up and leaking. This is an easy and cheap fix, but be careful removing the old gaskets as they can be stuck down pretty hard.

If you have a sunroof make sure the drains are cleaned out. There might be a drain at the base of your windshield that is clogged up and causing water to overflow into the foot area. I cannot remember if 115's do this, but 123 and 124 cars sure do.