An innovation by Kingspan Water Tanks. The Evolution MkIV pump system is a compact, integrated rainwater solution combining a Claytech submersible booster pump with built-in mains rainwater switching. The lightweight cover fits neatly on top of the tank, while automatically switching to mains water when tank levels are low or during a power failure. With integrated backflow protection and a float switch to help prevent dry running, it is our most popular pump system for residential homes.