Regulator Ofwat has said it is currently investigating all 11 water companies in England and Wales to determine if their sewage treatment facilities are causing environmental pollution. It expressed serious concerns about the industry's environmental performance. As part of the inquiry, Ofwat has issued formal enforcement notices to four companies: Dwr Cymru Welsh Water, Hafren Dyfrdwy, Severn Trent, and United Utilities.
United Utilities said in a statement: “We understand and share people’s concerns about the health of the environment and the operation of wastewater systems, including combined sewer overflows.” Severn Trent said it had “committed to going further and faster than anyone else in the sector” in relation to tackling sewage overflows. Both firms said they would “work constructively” with Ofwat in its investigation.