The straining tower at Lake Vyrnwy is an imposing castle-like structure standing 48 metres above sea level with a further 15 metres delving into the water. The lake itself sits in the heart of Wales and supplies Liverpool and its surrounding towns with water, after travelling along a 110km aqueduct which starts at the Straining Tower where any detritus is removed via a mesh filter. Built in 1881 in Gothic-revival architectural style as part of the heroic Vrynwy Dam project, the first of its kind in the world. This was the first of several long-distance water supply schemes in Britain which were vital to urban development in the late-Victorian period. Water was first supplied to Liverpool in 1892, where it eventually finds its way to Norton Water Tower, built in parallel at the same time as its sister tower 70 miles away to act as a balancing reservoir in the process of supplying water to the town of Runcorn and through to Liverpool through a tunnel under the River Mersey.

The system that feeds Norton Water Tower still works exactly as it did 125 years ago, and serves the same purpose despite such an increase in population, making it the largest UK tromboned pressure relief device currently in operation. Both towers were designed by George F. Deacon, the Chief Engineer of the Liverpool Corporation Waterworks Department, are now operated and protected by United Utilities. Standing above the surrounding landscape, Norton Tower has become iconic in the local area, and in 1983 it became recorded in the National Heritage List for England as a designated Grade II listed building. The Straining tower, along with the dam it feeds from, earned its Grade I status exactly 10 years later for its national importance as an outstanding achievement of Victorian water engineering, its exceptional completeness in structure and equipment, and its picturesque qualities.