Drinking water contamination alerts in Britain have surged by almost 300% in just five years, new data has revealed, with tap water repeatedly polluted by dangerous chemicals. Between 2020 and October 2025, 379 drinking water notices were issued across the UK, figures obtained from the Drinking Water Inspectorate show. The number of notices has climbed from 34 in 2020 to a peak of 131 in 2024, an increase of 285%. Notices are issued when water quality is compromised or at risk and can require boil notices or supply restrictions. South East Water issued the highest number of notices over the five-year period, with 51 alerts affecting parts of Kent, Surrey and West Sussex.