When you put water in the plant, where does the excess water go?

Are you referring to a specific project?

Ron, it will depend on your planter. Most planters have an attached bottom where overflow water will drain into it. The excess water will evaporate. If your planter does not have an attached drain saucer, the water will stay in your plant pot and too much water will drown your new plant. Just FYI.

What kind of "Plant" are you asking about? or do you mean some type of planter?

Technically it's called evaporation, a plant is a living organism, it lives & breaths, it breathes in carbon dioxide, that we expel & breathes out oxygen that we breathe in, so we are keeping each other alive, it expires like we perspire putting back the moisture into the atmosphere, making rain for all of use to survive, hence, no plants , no us !!!

Either water your plants in the kitchen sink and let them drain for a while after watering or use a saucer under the pot. I use clear glass saucers or you can buy plastic saucers. Some pots have attached saucers.

If you are using pots without drain holes, the excess water will settle in the bottom of the pot and if over watered, will eventually rot the roots of the plant.