Why is fresh water in the UK passed through filter beds?

Fresh water in the UK is passed through filter beds primarily to remove insoluble particles. This process is crucial because it helps to eliminate sediment, dirt, and other particulate matter present in the water source. The filter bed typically consists of layers of sand and gravel, which effectively trap these insoluble particles as water flows through.

By filtering out these particles, the clarity and quality of the water are improved, which is essential for subsequent treatment processes. Although other treatment methods might address contaminants and improve safety or taste, the primary function of filter beds is specifically geared towards the removal of suspended solids. This step plays a vital role in ensuring that the water is clean and safe for consumption before further purification treatments, such as chlorination or ozonation, are applied.