A water company has said it will pay £10 to each of its customers after it under-reported leakages.
Welsh Water says every customer will receive the rebate following an internal review.
The review found “governance and management oversight failures” which meant leak figures were higher than previously reported.
The amount of water used per customer was lower than first reported.
The company serves households in most of Wales, Herefordshire and parts of Deeside.
It said it will credit the £10 onto the accounts of its 1.3 million household and 100,000 business customer accounts in the coming months, costing it around £14m in total.
Welsh Water has said it will also allocate an extra £54m to tackling water leakages over the next two years.
The actual total leakage for 2021/22 was 240.3ml per day compared to 157.4ml per day as was previously reported by the company, which equates to 8.6 m3 per km of main per day.
Pete Perry, chief executive officer, said changes have been made to how leakages are reported by the company.
“We are very sorry and disappointed that this has happened,” he said.
“Whilst our robust assurance process ultimately identified the issue, there were failures in our governance and management oversight processes that allowed this in the first place.
“We have made the necessary changes to how we manage leakage reporting and closed the gaps in our reporting and governance processes.”
The regulator Ofwat is reviewing evidence provided to it by Welsh Water before it decides whether further investigation is needed.