For most, turning on the faucet for water, flushing the toilet or watering the lawn is such a natural, everyday activity that few think about the intricate series of pipes, motors, purifiers and systems that go into moving water from a source to a toothbrush. But underneath the feet and foundations of a town sits often hundreds of miles of pipeline—Round Rock has about 600 miles worth—and a system that regulates pressure to keep the water flowing.

But not all of the action takes place underground. In order to regulate and maintain pressure and water levels throughout a system, water towers are used to store treated water and manage flow. These massive concrete structures—which can cost abound $2 million each—are more than just advertising space for local schools and the city they provide water to; they're an integral piece of the system that keeps the water flowing.

1. One pipe typically controls both the intake and outtake from the storage area. Since storage tanks are used to regulate pressure and flow throughout a water system, pipes will direct water into the tanks when the system has lower demand, and thus extra water, and will open up to add water to the system at other times. By state law, water systems must maintain at least 35 pounds per square inch (PSI) of water pressure in their system at all times.

2. To ensure tanks do not become over-full, water tanks have an overflow pipe that will drain water from a storage tank and deposit it on the ground or in the surrounding area if a tank is too full.

3. Round Rock Utilities Director Michael Thane said the sides of water towers have to be painted and rehabbed every 15 years, but the city has done it out of cycle for some area schools, for instance, when they have won state championships. Thane said private companies have approached the city about putting company logos on them, but city policy is to deny any of those requests.

4. The storage tank holds treated water at varying levels in order to regulate the system. Though state law only requires 35 PSI at every connection, Round Rock, for example, has a goal of 50 PSI to err on the safe side, Thane said. State law also requires 100 gallons of elevated storage per connection, and Round Rock has about 30,000 connections, Thane said. That means the city must have at least 3 million gallons of elevated storage in the city.

5. Elevated water tanks must be at least 80 feet off the ground to help with system pressure. No actual water is stored the trunk of a typical elevated water tank, and water only passes through when flowing into or out of the tank. Instead, the interior houses access ladders, control valves and pipes, the inlet and outlet pipe, and more. Cylindrical storage tanks that do not have an open interior and are completely filled with water do not count as elevated storage until the water reaches 80 feet.