Welsh Water has secured a £230 million loan from the European Investment Bank (EIB) to help fund its five-year infrastructure programme.
The 15-year loan will help the company, which provides water and wastewater services to more than three million people, meet a £1.5 billion bill to invest in its network of pipes and sewerage sites across Wales.
The not-for-profit water firm expects the programme to keep its costs down, helping lower customer bills.
Projects include upgrading or rebuilding 12 water treatment plants and a £15 million scheme called RainScape to manage surface water.
Jonathan Taylor, Vice President of the EIB said: “Continued investment in UK water infrastructure is essential to allow customers to access clean drinking water and sanitation that is amongst the best in the world.
“The impressive project seen in Llanelli demonstrates a clear commitment to protecting rivers across the Welsh Water area from pollution.”