Understanding How a Water Storage Tank Works! This illustration shows the internal anatomy of a modern water storage tank designed for cleaner water, stable pressure, and longer system life. 1. The Fill Valve & Float automatically controls the water level, preventing overflow and maintaining efficiency. 2. An Air Jar (Vacuum Breaker) helps regulate pressure and protects the plumbing system from vacuum damage. 3. The Elevated Water Outlet is positioned slightly above the bottom to prevent sedimen