Making the Invisible Audible: A Simple Sound‐Emitting Water Level Meter

“Groundwater: Making the invisible visible” is the theme of the World Water Day 2022 and the title of the corresponding UN World Water Development Report (United Nations 2022). It describes our dilemma quite well: Groundwater is of vital importance, but being hidden, it is out of sight and out of mind. Hence, current efforts aim at increasing the awareness for this undervalued resource.