Australia: the world’s second driest continent, yet one of the highest consumers of Earth’s most precious resource – water. Future life on Earth relies on us conserving the water we have and planning for the prospect of reduced rainfall. In this activity, we give the power to the students as we explore our understanding of volume and water use, how much water we use in our everyday lives, and how we can reduce our usage to better support our environment. Playing with hundreds of foam blocks of all shapes and sizes to represent the resource, we tap into our inner mathematician to highlight the importance of turning the tap off where we can and making conscious efforts to minimise water waste at home, school and throughout our community.