South West Water has been rated the worst performer for pollution incidents and Northumbrian Water for permit compliance, the Environment Agency (EA) has revealed in a new report.

The agency said water companies need to do more to protect the environment despite a gradual improving trend in environmental performance over recent years.

Last year saw a rise in the most serious pollution incidents with 11 “Category 1” incidents. Previous reductions in serious (Category 1 and 2) incidents were shown to have plateaued with around one incident per week recorded.

The Water and Sewerage Companies’ Environmental Performance report rates how well the big nine water and sewage companies in England managed their impact on the environment in 2017.

It assesses a wide range of measures including pollution, managing sewage and complying with permits and compares individual company performance.

For the third year running, United Utilities and Wessex Water were the top performing water companies. They have been joined by Severn Trent and all three received the top four-star rating.

At the other end of the scale Northumbrian Water and South West Water received only two stars and were rated the lowest for their environmental performance.

The EA warned the two poor performers of the “urgent need” to improve.

Richard Warneford, wastewater director, Northumbrian Water Group, said: “We are pleased that the report shows our industry leading pollutions performance in 2017 and that we had 25 per cent less incidents than our nearest competitor.

“It has also outlined how we have improved in protecting and improving the environment; and minimised the environmental impact of our assets and activities – whilst delivering good performance and sharing good practice. This is demonstrated in that overall we achieved five ‘green’ ratings out of seven.

“However, our performance on discharge permit compliance was disappointing this year, although, the issues related to only seven of our sites, and we still achieved 96 per cent compliance.”

He added: “Six months into 2018 with zero compliance failures we are confident in turning previous issues around and we are pushing for 100 per cent discharge permit compliance.

“We have an ambitious approach to achieving our goals and will be aiming for four-star rating in 2018.

“Whilst we recognise we have areas in which we must improve, in many areas our pollutions performance is industry leading and we will carry this forward.”

A spokesperson for South West Water added: “We remain on track to deliver our business plan by 2020 and have achieved our best ever performance in wastewater in several key areas.  However, we fully recognise that more needs to be done and have an action plan in place to drive improvement.

“Under our revised pollution reduction strategy, we remain absolutely determined to achieve 100 per cent compliance with wastewater permits, zero serious and significant pollution incidents, a big reduction in other incidents and a further increase in self-reporting.

“Our continued focus on compliance at challenging sites and ongoing monitoring of their performance will ensure that our numeric compliance improves significantly during 2018.”

The Environment Agency recently set out a more ambitious programme of environmental improvements which water companies will have to make between 2020 and 2025 – totalling £5 billion of investment. 

Toby Willison, executive director of operations for the Environment Agency, said: “One serious pollution incident is one too many. We will always work closely with companies who want to do the right thing but we will take action against those who don’t.”

He added: “We expect to see a clear and continued focus on environmental performance in the next round of water company business plans to be submitted in the autumn.”

The four-star rated performers all achieved “green” status in six of the seven metrics.

Richard Hargrave, head of compliance at Wessex Water, said: “No other company has been such a consistent performer since the introduction of the EPA [Environmental Performance Assessment].

“This achievement has resulted from a lot of hard work across the business, not just the sewerage and sewage treatment operational staff but other parts of the company such as the compliance team, engineering and construction and water resources.”

Liv Garfield, chief executive of Severn Trent, added: “This is fantastic news and real validation of all the hard work the teams have put in over the past 12 months. This is now our third four-star performance in the last four years.

“We know that our customers want us to be great custodians of the environment which is why we put such emphasis on our performance in that area.

“But the fact remains that we can always do better – we constantly strive to be best in class and I’ll be challenging everyone to continually improve our performance in the years to come.”

The sector has been fined more than £21 million for poor environmental performance as a result of successful prosecutions by the EA.