Water regulator Ofwat has proposed an £11 million enforcement package after finding that Wessex Water failed to adequately operate, maintain and upgrade its wastewater network, leading to avoidable sewage spills across the region.
The investigation found that parts of Wessex Water’s infrastructure were not being properly managed, resulting in sewage being discharged from storm overflows when it should not have been.
The proposed package, announced on 11th November 2025, requires Wessex Water and its shareholders - not customers - to fund the full £11 million. None of the cost will be added to customer bills.
According to Ofwat, the money will be used to deliver environmental improvements beyond the company’s existing investment commitments. The programme will include support for private landowners to seal their sewer pipes and prevent groundwater entering the network, and measures to reduce spills at key storm overflows by bringing forward investment that would otherwise have taken place after 2030. It will also fund the installation of new monitoring equipment to improve management of flows at treatment works and storm overflows, as well as initiatives to help customers manage rainwater more sustainably on their properties.
This is the sixth case in Ofwat’s ongoing sector-wide investigation into wastewater management, which has so far led to enforcement action worth more than £240 million against other major water companies.
Lynn Parker, Ofwat’s Senior Director for Enforcement, said: “Our investigation found that Wessex Water failed to effectively operate, maintain and upgrade its wastewater assets, which meant there were spills from storm overflows when there shouldn’t have been.
“To their credit, the company has been one of the more proactive in investigating and rectifying the problems identified - but breaches remain which must be accounted for and corrected.”
Ofwat noted that without this agreement, it would have considered imposing a fine of around £10 million - equivalent to 2.5 per cent of Wessex Water’s annual turnover - with proceeds going to the Treasury. Instead, the £11 million package will be invested directly into service and environmental improvements for local communities.
A Wessex Water spokesman said the company “regrets the impact of its wastewater performance” and acknowledges “there is more work needed, particularly regarding groundwater entering the sewerage network.”
The company confirmed it supports the proposed enforcement package, believing the measures “will directly address the problem through actions like sealing pipes, additional monitoring, and initiatives such as water butts and rain gardens.”
Wessex Water added that it plans to invest £300 million by 2030 in sewerage infrastructure maintenance, including expanding key waste treatment sites across the region.
The announcement prompted a strong response from Liberal Democrat MPs across the South West, who accused Wessex Water of “environmental vandalism” and called for tougher regulation.
North Wiltshire MP Sarah Gibson was among the Liberal Democrat MPs who signed the joint statement condemning Wessex Water’s record, calling for stronger protections for local rivers and more decisive action from government.
In a joint statement, the MPs said: “Wessex Water has committed environmental vandalism for far too long, carelessly polluting beaches and rivers throughout the South West with filthy sewage.
“New enforcement is vital - but this fine alone won’t be enough to protect local families. No amount of money from Wessex Water can atone for the damage already done. We must ensure these reckless water companies put an end to sewage dumping and stop putting profit above people once and for all.”
The MPs also criticised the government’s record on water quality, describing its response as “too little, too late”, and urged ministers to deliver ‘blue flag’ protections for rivers and replace Ofwat with “a regulator with teeth.”
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