Yesterday (Tuesday 5 September), the BBC has reported on the quality of our rivers, lakes and seas, the role of storm overflows and an investigation into ‘dry spills’.

There were several issues raised in reporting that require further explanation, as set out below:

Why do storm overflows need to be used at all?

The sewer systems first constructed in the UK in the 1800s and early to mid 1900s were mostly built as combined sewer systems, so that wastewater (from toilets, bathrooms and kitchens) and rainwater were carried in the same pipe. Sewers constructed from the late 1900s onwards are largely separate systems, carrying wastewater and surface water in different pipes. However, we still have thousands of miles of combined sewers in our towns and cities - enough to stretch two and half times around the world.

The combined sewer system is designed so that at times of heavy rain or snow which exceeds (or overwhelms) sewer capacity, sewage diluted with water overflows into rivers and seas. That is what a storm overflow is. It is designed to prevent sewage backing up into properties and stops mains pipes bursting. There are strict permit conditions for when and how they should be used to protect our environment.

What is the government doing about it?

The government has set out our Plan for Water to tackle every source of pollution in our waters, and delivering more investment, stronger regulation and tougher enforcement.

That includes accelerating investment into better infrastructure over the next two years, supporting Ofwat’s new powers to tackle excessive dividend payments and using money from water company fines and penalties to support local environmental projects. This comes on top of the largest capital investment into infrastructure in the sector’s history – a £56 billion commitment.

The Plan is also driving up monitoring and transparency so the public can see what is going on – increasing the number of storm overflows monitored across the network from 7% in 2010, to 91% now, and with 100% expected by the end of the year. Thanks to increased monitoring we have been able to undertake the largest criminal investigation in the sector’s history into the potential misuse of storm overflows.

What is a dry spill?

A ‘dry spill’ is when a storm overflow is used on a ‘dry day’ – which is defined as no rainfall above 0.25mm on that day and the preceding day (24 hours). However, there are exceptions which must also be considered, such as in very large catchments with long drain down times. The Environment Agency carries out a detailed modelling process, looking at local rainfall gauges and drainage times – as well as Met Office data – to establish if dry spills have happened. When data indicates that dry spills may have occurred, this is followed by an investigation on a site-by-site basis.

Did companies allow ‘dry spills’ to happen last year?

This year, the Environment Agency is assessing data from nearly 15,000 storm overflows. Where the data indicates a dry spill may have occurred, this is followed by an investigation on a site-by-site basis to determine, for example, that data from rainfall monitors and drain down times are correct, as well as other factors. The data must be rigorous enough to stand up in court if the Environment Agency chooses to prosecute in the future.

The Environment Agency is currently finalising its analysis of 2022 data. If any company is found to have breached its permit, it will face enforcement action, up to and including prosecution. Since 2015, the Environment Agency have concluded 59 prosecutions against water and sewerage companies securing fines of over £150 million.

Has water quality got progressively worse in England?

The proportion of rivers that meet ‘good ecological status’ has remained around the same over the last 10 years. Since the major improvements seen in the 1990s when the water industry was privatised and the Urban Waste Water Treatment Directive came into effect, the rate of improvement has slowed due to an increasing population, ageing infrastructure, increased pollution risks and the pressure on our system from climate change.

It is also important to note that the natural environment takes time to recover, so there is a lag between our actions and benefits being seen. Past classification methods were also not as precise as those we have now. Comparing the latest results with those from 2009, which indicates 25% of rivers were in good ecological condition, is not possible. That is because significant changes have been made to the classification methods and monitoring networks over this period – reflecting increased transparency through improving scientific knowledge and monitoring programmes.

All the data is publicly available on GOV.UK via Catchment Data Explorer. Our water quality results are very similar other Northern European countries, which are comparable in terms of industrial histories, growth of urban populations and the need to balance the demands on the way we manage water from the agriculture sector, business, industry, navigation and the prevention of flooding.

Though the ‘good ecological status’ of water bodies has remained largely the same, other improvements have been noted. For instance, a recent study has found that freshwater macroinvertebrate biodiversity in English rivers has improved from 1991-2019. Levels of ammonia have reduced to just 15% of their levels in 1990 and phosphorus discharges from wastewater treatment works have reduced 80% since 1990.

In 2022, 93% of bathing waters – beaches or other swimming spots – met the highest standards of ‘good’ or ‘excellent’, up from just 76% in 2010. In the early 1990s, just 28% of bathing waters met the highest standards in force at that time.

Didn’t the government legalise the dumping of sewage?

No. Storm overflows have always been legal, subject to strict conditions. This has not changed. It is actually the opposite, discharges that were once legal will become progressively illegal due to tighter rules.

There have also been misleading claims around a European Court of Justice 2012 ruling, claiming that all storm overflow discharges are illegal. That is incorrect. See our previous blog for further information on this.

Is the government or its regulators doing anything about excessive dividends pay-outs or bonus payments?

Yes. We are clear water companies must not profit from environmental damage.

On dividends: Using new powers granted to Ofwat by the government, the regulator is ensuring company dividends are directly linked to environmental performance.

On bonuses for water company executives: Ofwat has outlined a new measure to ensure customers do not fund (via water bills) executive bonus payments where certain performance metrics have not been reached.

An Environment Agency spokesperson said:

We are conducting our largest ever criminal investigation into potential widespread non-compliance by water and sewerage companies at thousands of sewage treatment works. Our tough enforcement action has already led to over £150m in fines since 2015.

We will always pursue and prosecute companies that are deliberately obstructive or misleading – and work constructively with those driving improvements.

We are also improving how we regulate the sector – including expanding the number of officers focused solely on regulation, increasing compliance checks and recruiting more data specialists able to translate storm overflows monitoring data into stronger regulatory intelligence.

Water Minister Rebecca Pow said: 

The volume of sewage discharged into our waters is utterly unacceptable and it’s why our Plan for Water means more investment, stronger regulation and tougher enforcement, tackling every source of pollution and ensuring swift enforcement action is taken against those who break the rules.

Targets set by government to reduce storm overflows are very strict and are leading to the largest infrastructure programme in water company history - £56 billion over the next 25 years. Shortly, water companies will also publish actions plans for every storm overflow in England, something the Environment Secretary has personally pressed for.

More investment 

• As part of the Plan for Water, over £2.2 billion of accelerated investment will be directed into vital infrastructure, starting in the next two years, to improve water quality and secure future water supplies - with £1.7bn of this being used to tackle storm overflows. This is part of a £56 billion infrastructure investment that we require water companies to undertake – the largest in the sector’s history.
• The government is creating a new Water Restoration Fund, using money from water company fines and penalties to support local environmental projects, like re-meandering rivers and restoring habitats.

Stronger regulation

• We are driving up monitoring and transparency so the public can see what is going on – we have increased the number of storm overflows monitored across the network from 7% in 2010, to 91% now, and with 100% expected by the end of the year.

• We will be banning the sale of wet wipes containing plastic – subject to consultation – and writing to relevant producers and advertising authorities about ‘flushable’ labelling on wet wipe packaging.
• The government backed plans for the water regulator Ofwat to take action against water companies that pay out dividends to their shareholders despite failing to meet the required performance standards, and boosted their enforcement capacity with an additional £11 million funding increase.
• As a result of this government’s action, 91% of overflows are monitored throughout the year, reaching 100% cover by the end of this year. We have also demanded that every company publish this information in real time so that everyone can see what is happening.

Tougher enforcement 

• We are holding water companies to account on a scale never seen before. Since 2015, the Environment Agency has concluded 59 prosecutions, securing record fines of over £150 million against water companies. The Environment Agency has also launched the largest criminal investigation into unpermitted water company sewage discharges ever at over 2,200 treatment works.
• We are also scrapping the cap on civil penalties and significantly broadening their scope to target a much wider range of offences. This is toughening our enforcement tools and expanding where regulators can use them. This will deliver a proportionate punishment for operators that breach their permits and harm our rivers, seas and precious habitats.
• We have brought in unlimited fines for polluting water companies. This follows action from Ofwat to ensure dividends are clearly linked to company performance for customers and the environment, as well as tighter measures on water company executive bonuses.
• We have increased permit charges on water companies to fund more EA water company inspections, with new inspection targets.