Have you ever wondered what that giant tank on the hill was? You are looking at a water tank reservoir storing water for your community. Water reservoirs are a means to store both drinking (potable) and non-drinking water (non-potable). Reservoirs can be in the form of a lake or tank. Beneath the ground you can also find natural underground reservoirs where water is stored until it can be pumped, treated (cleaned) and delivered to homes.
Potable water tank reservoirs store water that has already been treated and is waiting to be delivered to homes and businesses. In California, due to the mountainous terrain, reservoirs are usually placed in higher elevations. The reason for placing the tanks higher than the homes and businesses is because pressure is needed to push water through the pipes. The water that leaves the tanks travels by gravity flow. The water pushes through the distribution system (pipes) and the pressure depends on the elevation and distance of the reservoir that provides water to a home. A water pressure regulator is a device that can be installed to regulate pressure to ensure the correct amount of pressure is present.
Reservoir tanks ensure that the correct amount of water is treated and ready to be distributed to the areas they provide water to. When people turn on the tap to take a drink of water, enjoy a shower or wash their hands, water travels directly from a nearby reservoir, through pipes and into homes. The process happens so efficiently that most people never think twice about where their water comes from or how it gets to them. Besides residential, commercial and industrial water demands, reservoirs also store surplus water held in reserve in case of high fire flow water demand. This ensures adequate water is supplied to fire hydrants when firefighting is needed.
“There are several benefits of a tank reservoir versus an open reservoir,” shares Liza Muñoz, Inland Empire Utilities Agency Senior Engineer. “Tanks allow you to store a large amount of water in a smaller footprint than in an open reservoir. They also avoid water evaporation, which can reduce supply. Tanks are designed to supply water at the appropriate system pressures needed to deliver the water.”
Inland Empire Utilities Agency (IEUA) has five above ground tank reservoirs to store treated recycled water for non-potable (not for drinking) water. The recycled water is stored in the reservoirs and then distributed to IEUA’s member agencies for non-potable use in agriculture, irrigation, industrial cooling processes, and groundwater replenishment. The water stored in these tanks comes from IEUA’s regional water recycling plants and are governed by California Title 22. Stringent water quality testing is conducted so that recycled water quality meets/exceeds regulatory standards in order to be reused for non-drinking water purposes.
Both drinking water and treated recycled water can benefit from being stored in tank reservoirs. Next time to you look up at a hill and see a tank reservoir, be sure to remember that inside that large tank there are possibly millions of gallons of water inside waiting to travel through your city.