Several of the UK's most prominent water companies have joined Severn Trent in submitting massive infrastructure investment proposals. : Britons face even higher bills as part of efforts to clean up the country's rivers, seas and beaches, the water industry has warned. Several of the UK's most prominent water companies have joined Severn Trent in submitting multi-billion-pound infrastructure investment proposals to slash the enormous volume of leaks and sewage discharges experienced in recent years.