A wishing well is a well that people throw coins into while making a wish. It is from European folklore to describe wells where it was thought that any spoken wish would be granted.
The idea that a wish would be granted came from the idea that water housed deities, or was a gift from the gods, since water was a source of life and often a scarce commodity.
The Native Americans, if they were to “borrow” something from a body of water, such as a river, they would always place something of value back into the water. Like a trade. Never “taking” and not giving back.
The Germanic and Celtic peoples considered springs and wells sacred places. Sometimes the places were marked with wooden statues, possibly of the god associated with the pool.
Water also was seen to have healing powers and therefore, wells became popular with many people drinking, bathing or just simply wishing over it.
The biocidal properties of both copper and silver (the two metals traditionally used in coins), were thought that the properties themselves, provided safer drinking water.
When making a wish, people would first utter the wish, then, one would generally drop a coin in the well. That wish would then be granted by the guardian and dweller, based upon how the coin would land at the bottom of the well.
If the coin landed heads up, the guardian of the well would grant the wish, but the wish of a tails up coin would be ignored.