South West Water: What are its 'range of failures' and why does it need to spend millions?

South West Water (SWW) will have to spend £24 million to improve the region’s water infrastructure after an industry regulator investigation. 

The company faced backlash from environmental campaigners, surfers, and swimmers in May 2025 over sewage pollution.

One year ago, the seaside town of Brixham made headlines across the country as it grappled with an outbreak of a diarrhoea and vomiting illness, following a contamination of cryptosporidium in the water supply.

What has happened?

The industry regulator Ofwat’s investigation found a "range of failures" in how the company managed its wastewater treatment works and sewer network.

These failures resulted in SWW spilling wastewater into the environment when it should not have done.

It said it "failed to meet its legal obligations", pointing to a lack of adequate management systems, including oversight from the senior leaders and board.

Lynn Parker, Ofwat's Senior Director of Enforcement, said: "We’ve found significant failings that have led to more spills than the law allows over a significant number of years so we consider this to be systemic failings.

SWW has proposed spending £24 million under an "enforcement package" to target storm overflows, tackle sewer misuse, and provide funding for environmental groups.

This will be funded by the company and shareholders.

As a result, it has avoided being fined by Ofwat which would have been the lesser amount of £19 million - 6.5% of its annual turnover - going back to the Treasury.

This investigation is part of work by Ofwat and the Environment Agency to review all water and wastewater companies in England and Wales. 

What is wastewater treatment?

‘Wastewater’ includes surface water running off roads and roofs and ‘foul sewage’ from toilets, sinks, and showers.

This water is treated through chemical and biological processes and then pumped into rivers and the sea.

Initially it’s screened to get rid of large solids like wipes and sanitary towels and then smaller elements like grit from the roads.

‘Settling’ in large tanks allows the sludge to accumulate on the bottom so cleaner water can go on to be aerated by oxygen being added. After further settling, clean water is released into rivers.

SWW has 655 Waste Water and Treatment Works (WWTW) which it says is one of the highest amounts across the industry.

They treat 585 million litres of sewage daily, serving 1.8 million customers across Devon, Cornwall, and parts of Somerset, Dorset, and the Isles of Scilly.

What issues have South West Water faced?

• May 2025: the Government announced four criminal investigations will be carried out into SWW following hundreds of reports and complaints about sewage pollution on beaches.

• April 2025: hundreds of homes and businesses were left without water for several days after a burst water main in Plymouth. An Environment Agency report showed in 2024 SWW had 56,000 spills (28,000 in 2023). Duration of storm overflow usage increased to 544,000 hours (531,000 in 2023)

• March 2025: the Environment Agency won a case against SWW which tried to prevent 12 charges relating to sewage discharges in Cornwall being taken forward in a prosecution. It’s facing charges for illegal discharges and breaches of environmental permits including at Hooe Lake Sewage Pumping Station, Polperro Harbour and Bodmin Road Plymouth between 2016 and 2021.

• Nov 2024: SWW pleaded guilty to five charges relating to illegal water discharges and breaching environmental permits in Plymouth and Polperro.

• Sept 2024: More than 300 residents and businesses in Exmouth threatened legal action against SWW because of their concerns over sewage spills on the beach leading to a series of no-swim warnings.

• July 2024: SWW was ranked among the worst performing water companies in the UK with the Environment Agency's assessment reading "requires improvement" after the company discharged sewage into rivers and seas more than 58,000 in the previous year.

• May 2024: More than 16,000 households and businesses in Brixham were told to boil their drinking water after the cryptosporidium parasite was found in the supply, leading to an outbreak of diarrhoea and vomiting. Two people were taken to hospital while hundreds of others fell ill.

What is South West Water addressing the issues?

South West Water has taken already taken some steps to address its compliance issues.

It says it has invested more than £16 million to remedy the 21 WWTW that failed to meet requirements.

It is in the process of delivering a storm overflow reduction plan investing to reduce spills and greater oversight of its compliance with environmental obligations.

Noah Law, MP for St Austell and Newquay, has had the company's CEO Susan Davy on 'resignation watch' for some time.

He said: "I think they have a long standing plan in place for different asset management periods but what I want them to do now is accelerate that pace and show they know the sense of urgency residents have around this.

"I would urge a real caution of Susan Davy as to whether she looks at taking her bonus this year after all of this news."

When asked if Davy should resign, Louise Rowe, SWW's Director of Compliance, said: "Susan became CEO in 2020. Some of the areas are historical.

"Under her leadership SWW has significantly upheld the governance, we’ve put hundreds of millions of pounds into the wastewater activities and all of that has been recognised by Ofwat in their report that improvements have happened.

"We will continue to make the improvements needed where wastewater activity needs it across our beautiful region. "

South West Water CEO, Susan Davy, said: “We are pleased that Ofwat has completed its review into wastewater at South West Water as part of its sector wide investigation.

"For South West Water this related to historical issues. I have always said that when things go wrong, it is how we respond and put things right and that is exactly what we are doing.

"In response to Ofwat’s findings, we have proposed a ringfenced investment programme of £24m to spend more to further reduce spills, tackle sewer misuse and establish a Nature Recovery Fund, benefiting environmental groups in Devon and Cornwall and the wider community.

"This is in addition to the £760m we are already investing over the next five years to reduce the use of storm overflows across the region."