Next to the Delft water tower stands the associated pump house with an underground clean water cellar, which was originally used to store two million litres of water. This structure, dating from 1918–1919, is located on the grounds of the former municipal cemetery (1829–1874), now known as the Kalverbos, and forms part of the water tower complex and the protected cityscape of Delft. The impressive space was renovated in 2022 based on a design by DP6 architecture studio and now houses RADIUS, a centre for contemporary art and ecology.