Dŵr Cymru has put forward plans to increase the average water bill by around 26 per cent to £120 a year to help it improve services.

The water company has submitted its proposed Business Plan for 2025-30 to Ofwat, the water industry regulator.

The not-for-profit company says the plan will result, if approved, will lead to £3.5 billion investment to improve water quality, reduce leaks and reduce its impact on the environment.

Welsh Water says it is committing to invest nearly £1.9 billion in the environment between 2025 and 2030 – 84% more than across 2020-25. This will include substantially reducing phosphorous discharges from wastewater treatment to rivers in Special Areas of Conservation and starting on a multi-AMP programme to stop its network of 2,300 storm overflows causing ecological harm to rivers in its operating area.

In order to fund the investment, the water company says the average monthly bill will need to be £5 higher in 2025, and £10 by 2030.

Dŵr Cymru says its own research has shown that 84 per cent of customers find the plan acceptable.

Welsh Water Chief Executive Peter Perry said: “We have been able to keep bills flat or falling in real terms over the last 10 years, but we now need to make a material investment in our water and wastewater systems to meet the challenges of climate change, protect our rivers, and improve the resilience of our water supplies. Our research shows that the majority of our customers accept that this investment is necessary and should not be postponed. For our part we will continue to drive innovation and efficiency of our operations to reduce costs wherever we can.

“We are only too conscious of how difficult the last few years have been for our customers and this is why our plan includes significant additional support for customers who are struggling to make ends meet.”

Alastair Lyons, Chairman of Glas Cymru, added: “We believe that the plan represents ambitious progress towards meeting the objectives of our long-term strategy Welsh Water 2050, while representing good value for customers in terms of what will be delivered. Our £3.5bn investment programme will also bring significant opportunities to increase our contribution to the Welsh economy, supporting thousands of jobs across Wales.”

The proposal has been criticised however, with Dwyfor Meirionnydd MP, Liz Saville Roberts, saying: “Just imagine if we had full control over Welsh water

“If the people of Wales got a fair price for the billions of litres of water that boost the profits of English water companies every year. Water is the oil of the future.”

Welsh Conservatives Shadow Climate Change Minister, Janet Finch-Saunders MS also criticised the proposal, saying: “It’s completely unacceptable of Dŵr Cymru to raise bills when Dŵr Cymru customers already experience the second highest average bill in Wales and England. Along with this, the CEO’s salary is a whopping £332,000 (not including pension contributions and bonus payments). This will understandably frustrate and anger hard-working customers.

“As we regretfully know, nearly a quarter of all sewage discharges in the whole of England and Wales are in Wales, with Welsh rivers making up six of the top 20 rivers in England and Wales for the overall highest number of sewage dumps.”

Welsh Water’s Business Plan for 2025-2030 has also been scrutinised by the Independent Challenge Group (ICG) to ensure that it appropriately reflects the priorities of customers as well as those of regulators and other stakeholders.