Once it is made safe to drink, the water is transported via a network of closed, cast-iron or steel pipes to tanks which are usually placed on high ground. These could be underground tanks on the top of hills or water towers.
Water tanks and towers are interacting storage points on a hydraulic grid. This ensures there is regular and sufficient pressure within the system in accordance with the rate of consumption.
They also provide an emergency backup should there be an incident within the system or an unusually steep rise in consumption.

Water Cycles