Liberal Democrat MP Caroline Voaden has hit out at the Government and water companies for “purposefully muddying” the truth regarding the scale of water pollution.

New statistics from the Environment Agency reveal that in 2025, sewage was dumped by South West Water for a total of 407,006 hours. 

However, these figures only show the duration and number of spills - failing to convey the environmental damage being caused.

Under current regulations, water firms are only required to monitor the number and duration of sewage spills, but not the volume of sewage discharged. 

Ms Voaden is calling for an immediate end to the ‘Great Sewage Cover-up’, saying “You wouldn’t go into a pub and ask for three and a half seconds of Guinness, so why are we measuring sewage spills in this way?”.

The Liberal Democrats are calling for water companies to be required to monitor and report the volume of sewage dumped, adding that water companies cannot get away with deliberately obscuring how much they are polluting our waterways with sewage.

Responding to the figures, Caroline Voaden MP for South Devon said: “These statistics are absolutely shocking, but they are only the tip of the iceberg.

“The truth about how much sewage is being spilled into our rivers, lakes, and seas is unclear thanks to the government letting water companies off the hook.

“The public deserves to know the truth. That’s why I’m calling on the government to end the Great Sewage Cover-up, and force South West Water to record the volume of sewage spilling into our local waterways.”

Conservative MP for West Devon, Rebecca Smith, has agreed that improving how sewage discharge is measured could be useful, but questions the Lib Dems’ potentially half-baked demands.

"There is a clear case for improving how sewage discharges are measured,” says Ms Smith. “Particularly if it provides a more accurate picture of their environmental impact.

“It is also important to recognise the progress already made. In 2010, just 7% of storm overflows were monitored. But by 2023, that had reached 100 per cent, which is why the scale of the issue is now properly understood.

“However, the focus cannot rest solely on collecting more data and any move towards volume measurement must be proportionate, reliable, and deliver genuinely useful insight.

“The priority should be reducing, and ultimately preventing, sewage discharges altogether. I recently met with a company developing technology that could remove the need for storm overflows entirely, and I would much rather see South West Water working with innovators on solutions that tackle the problem at source.

“It would also be helpful to understand what the Liberal Democrats see as the next step beyond measurement. Better data is valuable, but it must be matched with a clear plan to deliver tangible improvements.”

South West Water totaled 46,164 spills in 2025, the third highest in the country. This figure is lower than 2024, when there were 56,173 spills over 544,439 hours, and 2023, with 58,249 spills over 520,737 hours, but is an increase from previous years.

In March, South West Water admitted to 18 illegal pollution offences across Devon and Cornwall over a six-year period. Sentencing is due on June 4, 2026.