South West Water is set to pay £24m after the water regulator found it spilled wastewater in the environment when it should not have done.
Ofwat said its investigation found a “range of failures” in how the Exeter-based water company managed its wastewater treatment works and sewer network. This meant it did not meet its legal obligations.
The £24m enforcement package was proposed by South West Water, to be paid by the company and its shareholders, to invest in its systems and address the failures.
This includes investing £20m over the next five years to reduce spills from specific storm overflows.
In June, South West Water's owner, Pennon, said rising water bills would help fund its £3.2bn investment plans, as losses deepened for the utility firm.
The company, which also owns Bristol Water, Bournemouth Water and SES Water, said a record year of investment, along with encouraging its customers to use less water to save money, had affected its annual profits.
Pennon confirmed in March that a major water contamination incident in Devon last year had pushed up costs by £36m.
Just over a year ago the diarrhoea-inducing cryptosporidium was discovered in a reservoir, prompting 17,000 households in Brixham to boil their drinking water for eight weeks.
In February, Pennon chief Susan Davy told MPs she had “regret” for the pollution incidents caused by the company.
She admitted to ministers at the time that "from time to time things do go wrong". There were 194 individual pollution incidents across the Pennon group between 2023 and 2024, and the company was fined £2.2m in 2023 for illegal sewage spills spanning four years across Devon and Cornwall.