Welsh water company Hafren Dyfrdwy has agreed to pay £280,000 following "unacceptable" failures that resulted in sewage spills, industry regulator Ofwat has announced.
The watchdog stated that the utility had "failed in its duties to deal effectively with wastewater and sewage".
Hafren Dyfrdwy, a subsidiary of Severn Trent, provides water and sewage services to approximately 109,000 customers across north-east and mid- Wales.
The firm has proposed a £280,000 package of remedial measures to be implemented by 2030 to tackle the issues uncovered during Ofwat's investigation, with the costs prohibited from being passed on to customers through increased bills.
Ofwat's inquiry revealed that the company had failed to maintain adequate drainage, manage the contents of its sewers effectively, and lacked the necessary processes and systems to fulfil its obligations.
The announcement follows Hafren Dyfrdwy being permitted to raise customer bills by £54, or 9%, to an average of £635 in the 2026-27 financial year.
Lynn Parker, senior director for enforcement at Ofwat, said: "Our investigation found unacceptable breaches by Hafren Dyfrdwy, which have resulted in excessive spills from storm overflows.
"We are clear this is unacceptable and now expect the company to focus on putting things right so that customers can regain trust in their water company and the critical service they provide."
Hafren Dyfrdwy, which means Severn Dee in Welsh, is required to implement a series of measures, including the installation of two storm water balancing tanks to cut spills, alongside partnering with a local preservation trust to assist in the creation of a wetland habitat.
This represents the ninth case in Ofwat's industry-wide sewage investigation, which the regulator says has already secured upwards of £300 million in enforcement packages and fines.
Ms Parker commented: "We understand that the public wants to see transformative change.
"That is why we are prioritising this sector-wide investigation, which is holding companies, like Hafren Dyfrdwy, to account."