How much sewage is spilled into rivers, lakes and the sea near you?

Water companies released record spills of raw sewage into the sea and rivers in England in 2023.

Rules allow a limited discharge of excess sewage during periods of excess rain, but there is also evidence of "dry spills", which can damage the local environment and pose a health risk to swimmers.

Spill data for the devolved nations is released separately. Northern Ireland does not currently monitor real-time spills and although Scotland has made efforts to increase monitoring, it only collects data from 27% of spill sites. Data for Welsh water companies is released in July.

The latest data for 2024 is expected to be released on Thursday.

Sewage spills into England's rivers and seas by water companies more than doubled in 2023.

According to the Environment Agency, there were 3.6 million hours of spills, compared to 1.75 million hours in 2022.

Water UK, the industry body for sewerage companies, said the level of spills was still "unacceptable", but that it had a plan "to end water sewage flowing into all waterways" which involved significant infrastructure upgrades.

Water bills are expected to rise by an average of £123 annually from 1 April in England to help pay for this.

The government has also launched an Independent Water Commission chaired by former deputy Bank of England governor Sir Jon Cunliffe to look at improving the performance of the sector.

Most of the UK has a combined sewerage system, meaning that both rainwater and wastewater - from toilets, bathrooms and kitchens - are carried in the same pipes.

Wastewater is usually sent to a sewage treatment works.

But capacity can sometimes be exceeded during heavy rainfall, especially if dry ground cannot quickly absorb large quantities of water.

This could lead to inundation of sewage works and potential flooding of homes, roads and open spaces.

The system is therefore designed to overflow occasionally, and discharge excess wastewater into the sea and rivers from combined sewer overflows (CSOs)

According to industry regulator Ofwat, some water companies have been "routinely releasing sewage" outside times of heavy downpours, in breach of their permits - known as dry spilling. It has said this is a result of companies failing to managing their wastewater treatment plants leading to sewage overflowing into rivers and lakes before being treated.

Last year, the BBC uncovered 6,000 potential dry spills by England's water companies in 2022.

Even if it is raining, water company permits also require them to treat a minimum amount of sewage before releasing it.

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There has been growing public anger over the level of sewage discharges and the quality of the country's waterways.

Environment Secretary Steve Reed has ruled out bringing England's water industry into public ownership saying it would cost up to £100bn. And there is no guarantee that a public model would result in fewer spills - Scottish Water is a publicly owned water company and recorded more than 100 spills per overflow in 2023, more than three times that in England.

In October 2023, Water UK, the industry body, announced plans on behalf of its members to almost double spending to pay for upgrades and cut sewage discharges. It said this would be the "most ambitious modernisation of sewers since the Victorian era".

But there has been criticism from environmental campaigners that customers' bills will have to rise significantly to help pay for a share of these changes, whilst water companies continue to pay out dividends to shareholders.

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In March, the government introduced the Water (Special Measures) Bill which aims to address some of these concerns. The bill hands regulators the power to block bonuses for water company executives and bring criminal charges against them repeated sewage spills have been due to "their neglect".

Ofwat and the Environment Agency are still continuing with their investigations into all water companies in England and Wales.

In August, Ofwat announced the first tranche of fines in its investigation. It is proposing a combined £168m penalty for Thames Water, Yorkshire Water and Northumbrian Water for failure to adequately invest in their infrastructure, leading to repeated sewage spills.

In May 2024, a team of the UK's top engineers and scientists warned of the growing public health risk from human faeces in the country's rivers, and called for more regular testing.

The presence of faeces can expose people to bacteria such as salmonella and E.coli, which cause diarrhoea and vomiting, or viruses like hepatitis A which can lead to liver infection.

The same month, thousands of residents in Devon were told to drink bottled water after their supply was contaminated with the cryptosporidium parasite - possibly as a result of a faulty valve on private land. Consumption of the parasite can cause prolonged diarrhoea.

Every week between May and September, the Environment Agency measures the water quality at "bathing sites" across England, and in some places it issues daily pollution risk forecasts. It is also proposing to extend the bathing season which would provide year round testing.

You can search its website by location. There are similar websites where you can find out about beaches and bathing water in Scotland, Wales or Northern Ireland.

And at the end of last year Water UK - the industry body - launched the National Storm Overflow Hub where almost real-time discharges can be seen across all of England's overflow points. But this does not contain data on the volume of sewage discharge or the presence of organisms carrying faecal-oral disease in the water.

Sewage spills have only been routinely monitored for a few years, so it is difficult to tell exactly how they have changed over time.

However, overall water quality has been monitored for decades. This also accounts for other sources of pollution, such as agriculture.

In May 2023, the Environment Agency said that 16% of assessed surface waters in England achieved "good" ecological status, including:

• 14% of rivers and lakes
• 19% of estuaries
• 45% of coastal waters
• 93% of designated bathing waters

Water quality is generally higher in other parts of the UK.

In Scotland, around two-thirds of surface waters are classed as having "good" ecological status.

In Wales the figure is 40%, and in Northern Ireland 31%.