Welsh Water is to spend £7 million to help fund lower bills for low-income households over the next year.
The company, which is owned by its customers, helps around 90,000 customers who struggle to pay their water bills, increasing to 100,000 by 2020.
Average household bills will increase by 1.8% to £439 in 2018-19, although the company said some bills will fall.
A record £430 million is being invested in capital projects, including a new pumping station in Usk, replacing pipes in Anglesey, new waste water treatment works in Pembrokeshire and improvements to bathing water quality in the popular resorts of Tenby and Saundersfoot.
Welsh Water chief executive Chris Jones said: "Today's investments are a direct benefit of our unique not-for-profit way of working, which allows us to invest the money we make back into the business and to benefit our customers.
"Our increased support of £7 million for our lowest-earning customers demonstrates our continuing commitment to supporting those who genuinely struggle to pay their bills - something which our customer consultations have shown is a strong priority for the people we serve.
"We will continue to work with a wide range of agencies and support organisations to promote our social tariffs to those that need help, while pursuing those who could pay, but choose not to, so that everyone pays their fair share."
Tom Taylor, chairman of the Consumer Council for Water in Wales, said: "Even the smallest increase in bills can be a tipping point for customers that are already struggling to pay so we are very pleased to see Welsh Water investing more in supporting households on a low income.
"Opting for a water meter can also save some households more than £100 a year and about two thirds of bill payers are still unaware they have two years to trial one with the option to switch back free of charge. "