Ofwat, a government regulator, is now investigating South West Water over its recent environmental performance and sewage spills from storm overflows.

It comes as part of its investigation into how all wastewater companies in England and Wales manage their wastewater treatment works. Ofwat is also currently investigating Anglian Water, Northumbrian Water, Thames Water, Wessex Water and Yorkshire Water.

It said that the move to look into South West Water was prompted by 'ongoing concerns' and the water company's latest environmental performance.

South West Water has been served with a formal notice to gather further information for enforcement purposes.

Ofwat Chief Executive David Black said: "The serious concerns we identified last year prompted our initial focus on five companies. As we gather and analyse more information, including data on storm overflow spills, our concerns have grown further about South West Water's operation of its wastewater assets and environmental performance.

"We have now opened enforcement cases against the majority of wastewater companies in England and Wales. From what we have seen so far, the scale of the issue here is shocking – companies must resolve any problems at wastewater treatment works and do so quickly. Where they have breached their obligations, we will not hesitate to act."

Ofwat also said that it expects all water companies to make quick progress, and it is working with the Environment Agency which is carrying out a criminal investigation into companies' compliance with environmental permits. The regulator could fine water companies up to 10% of their annual turnover.

A South West Water spokesperson said: "South West Water notes the announcement by Ofwat today to include it in its ongoing investigation into water companies.

"We are taking Ofwat's decision very seriously, we will provide any further information required as part of its review into South West Water. It is important that Ofwat and the public can have ongoing confidence in our commitment to the environment. Earlier this year we conducted a line-by-line review of our plans and announced our largest environmental programme in 15 years.

"This will reduce our use of storm overflows, maintain our region's excellent bathing water quality standards all year round and reduce and then remove our impact on river water quality by 2030. We will continue to work openly and transparently with Ofwat as part of their industry-wide activity."

Click here to view 2021 sewage spill data in your area on an interactive map.