Question

How plants get rid of the extra water

Answer 1

through some processes such as transpiration and guttation

Answer 2

Plants are just not animals. They can't sweat or urinate.
So, by transpiration and guttation, they lose the excess water.
In transpiration, the plants lose excess water through aerial parts such as stem, leaves, etc..
In guttation they lose excess water along the margins of the leaves on the tip of the veins through hydathodes in high hydrostatic pressure.

HOPE THIS HELPS!!