Over the years, people have asked me about the purpose of elevated water storage tanks, also known as “water towers”. Even people who are knowledgeable about the many state-of-the-art systems that ensure that the community has a continuous supply of clean water often don’t understand what purpose water towers serve in helping us deliver safe, clean, reliable water. Beyond being striking landmarks amid the landscape, often times reminding us of the name of the town we’re in, what purpose do water towers serve?
Their question is understandable, since water towers largely rely on two physics properties that are as old as the earth itself: gravity and pressure. There is really nothing complicated about water towers, especially when compared to some of the science and technology at work in, for instance, a modern water-treatment plant. However, water towers remain a critical part of a community’s water supply, especially in times of emergency.
Think about the last time there was a storm, an accident or other event that caused you to lose power or phone, internet or television service. What happened to your water? Chances are, regardless of what other utilities shut down, your water still flowed reliably from the tap. Water towers often “come to the rescue” in such instances, because they operate on pressure and gravity. This is also why water towers do “tower” above the landscape. When constructing an elevated tank, engineers calculate how tall it needs to be to provide enough pressure to supply the community being served. Elevated tanks serve as a “water bank in the sky”, holding a supply of water which can reach your tap (or the nearby fire hydrant in the event of a fire) by gravity, without the use of electricity.
But water towers are useful for more than just emergencies. For many community water suppliers—and, ultimately, the people they serve—water towers save on the cost of water-supply systems, as well as wear and tear, because they assist water-pumping equipment. Frequently, during peak water-supply hours, when more “pumping power” is required to meet high water demand, a water supplier will draw from the water tower to augment its pumping capacity (sort of like when you use your credit card to make a purchase at the coffee shop, rather than stopping at the ATM every single time you buy a cup of coffee). This means lower costs for pump operation.
You may wonder where all the water in a tower comes from. It comes from the same source as the water in your home! At nighttime, when most of us are sleeping and demand for water is very low, the Water Company continues to treat water for public use, and it pumps the excess water to the tank to refill the floating “bank” for use – for tomorrow’s peak, and for any unforeseen emergency.
For having such a simple method of operation, water towers really do play a huge role in our everyday lives. Now if only my real bank account would re-fill every night, the way our “water bank in the sky” does.
Nice article, Gary! I like how you put it in terms that the average person can understand. Good analogy.
___123___Look up at the sky. It’s a tower. It’s a “water bank”. It’s water security! : American Water – Water Street___123___
Well said. I might have used potential and kinetic energy terms at the risk of losing the audience!
As a Water Commissioner in my own town, we also consider it a benefit of replenishing water to the tank overnight by using off-peak electric rates.