Occasionally when a trunk main’s flow is reversed, many years of accumulated sediment will be suspended, leading to increased turbidity or lack of clarity, potentially affecting thousands of consumers. Another reason is when there is an older infrastructure. With many water systems having elements that are up to 100 years old, trunk main deterioration is now becoming an issue – leading to increased pipe debris. Changes to the network like overhauls, changing flow rates, bursts and valve operations can also trigger the need to clean pipework. Biofilm build-up can lead to many issues like an increase in bacteria levels and a loss of chlorination levels which indicate that the mains need cleaning.