There was water in the tanks at the top of the towers.

Joseph Paxton was first and foremost a gardener, and his layout of gardens, fountains, terraces and cascades left no doubt as to his ability. One thing he did have a problem with was water supply. Such was his enthusiasm that thousands of gallons of water were needed in order to feed the myriad fountains and cascades which abounded in the Crystal Palace park. The two main jets were 250 feet (76 m) high.

Initially, water towers were constructed, but the weight of water in the raised tanks caused them to collapse. Isambard Kingdom Brunel was consulted and came up with the plans for two mighty water towers, one at the north and the other at the south end of the building. Each supported a tremendous load of water, which was gathered from three reservoirs, at either end of and in the middle of the park.