Looking at municipal water usage per capita,

US uses 175.9 m3 per capita

Germany uses 236.5 m3 per capita

Czechia uses 57.5 per capita

So individuals in America (i.e. showering) do not use abnormally high amounts of water. The country in total uses more water because we have more farming and more industry than Germany or Czechia.

https://www.worldometers.info/water/us-water/

https://www.worldometers.info/water/germany-water/

https://www.worldometers.info/water/czechia-water/