"Water firms in England have been found to have 'passed' thousands of pollution tests without actually conducting the checks. An investigation revealed that between 2021 and 2023, over 5,000 samples taken at sewage plants were recorded as 'no-flows', despite no actual testing being done. The Environment Agency has since announced changes to its rules to plug this loophole. Water firms claim there were legitimate reasons for these 'no-flows', such as blockages or planned maintenance. The regulator is investigating these claims and will review the companies' performance."

Source: https://www.theguardian.com/environment/2024/oct/26/water-firms-england-passed-pollution-tests-never-carried-out-self-monitoring