In a year marked by environmental trials, rivers in Street and Glastonbury, as well as other parts of the country, have become the unfortunate hosts of an increase in raw sewage discharges.

Today, Water UK, the industry body representing England's nine water and sewage companies, apologised for their slow response to the issue.

Despite acknowledging the oversight and pledging to boost funding for sewer system upgrades, a report from 2022 confirmed that raw sewage ended up into rivers and seas for a total of 1.75 million hours - that's an average of 825 times a day.

The crisis hits home in Mendip, where 89 out of 92 storm overflows were monitored last year. An astonishing 1,837 spills were counted by the Environment Agency, amounting to a total duration of 12,078 hours - the equivalent of raw sewage entering the water system for 503 non-stop days.

• At the sewage plant on the outskirts of Shepton Mallet, there were 426 hours of sewage overspills into the River Sheppey reported. That's an unbroken stream of pollution for about 18 days, spread over 36 instances.
• The story repeats itself at the Pilton Water Recycling centre, albeit slightly less severe. Overflows occurred 23 times, spewing into Whitelake tributary for a total of 382 hours. This amounts to 16 full days of unabated pollution.
• At Havyatt Pumping station, on the outskirts of Glastonbury, spills were reported 22 times, lasting 191 hours or equivalent to 8 full days.
• The stretch of the River Brue by the Butleigh Sewage Treatment Works been hit hard, facing 106 sewage overspills. These lasted for 1,770 hours, equivalent to 74 days of continuous contamination.
• The Wessex Water Recycling Centre, discharging into the Mill Stream and Brue between Street and Glastonbury, is another site of concern. With 48 incidents lasting 511 hours, the local ecology has faced around 21 days of pollution.
• Street has not been spared either. The Street Main Pumping Station discharged into the tributary of the South Drain 29 times for 109 hours or five days. The Middle Brooks pumping station and Farm Lane Centre in Street also faced spills, with the former seeing four spills over 24 hours and the latter experiencing 14 spills over 15 hours.
• Meanwhile, the Glastonbury Water Recycling Centre saw a parallel story with 48 spills into the Mill Stream and the Brue amounting to 511 hours, equivalent to 21 days.
• At Porchestal Pumping Station, 18 spills polluted the environment for a total of 56 hours, while the area around Meare Waste Water Treatment works witnessed 59 spills for a cumulative duration of 613 hours or an equivalent of 26 days.
• The area around the Wookey Water Recycling Plant saw 62 spills into the River Axe for 1,104 hours, an equivalent of 46 days.

Storm overflows are part of an older type of sewer system called a combined sewer system. These sewer systes carry both surface water (run-off from roof gutters, patios, driveways and some highways) and foul water from homes and industry together in one pipe. The combined sewage is then transported to a water recycling centre to be treated. During a storm event, heavy or prolonged rainfall can rapidly increase the flow in a combined sewer and cause it to become overwhelmed.

Storm overflows are designed to release excess sort water into the river or the sea when this happens, to prevent sewer flooding. Media reports suggest water companies 'dump raw sewage', but this isn't accurate. This implies we can control when they operate and what is released is highly polluting. However, we have no control over when they operate and the discharge is heavily diluted by rainfall.

We currently monitor around 80% of storm overflows in our region, which shows when they operate and how long for, and have a programme in place to install monitoring equipment on all storm overflows by 2023. We provide updates when our storm overflows near bathing waters operate. We also give this information to organisations, including Surfers Against Sewage and local authorities. - Wessex Water

Swimming in water where untreated sewage is discharged can lead to serious illnesses such as stomach bugs, which may cause diarrhoea and/or vomiting, as well as respiratory, skin, ear and eye infections.

But it is more than a public health concern - wildlife including fish and insects can also experience kidney issues and die from sewage pollution.

As storm overflows should only operate during periods of intense rainfall, any foul water released from them will be very dilute because of the large volumes of rainwater flowing through the sewers, so they have very little environmental impact.

The Environment Agency is responsible for river and bathing water quality and it regulates intermittent discharges from storm overflows through environmental permits. The main polluting load of the contents of a sewer should flow to the treatment centre, allowing very dilute sewage to overflow when the sewer capacity is exceeded.

When storm overflows operate, the dilute sewage contains faecal bacteria, but their operation does not mean a bathing water's quality is necessarily unfit for swimming. Bacteria generally do not survive long outside host organisms and are especially fragile when exposed to sunlight in seawater. - Wessex Water

Today, an apology was issued by Water UK, the industry body which represents England's nine water and sewage companies.

Ruth Kelly, Water UK chair, told the BBC: "We're sorry about the upset and the anger from the fact that there have been overspills of untreated sewage onto beaches and into rivers over the past few years. We're sorry that we didn't act sooner, but we get it."

Alongside the apology, the companies promised to triple funding available for sewer system upgrades, provide the public with "near real-time" data on sewage spills and cut spills by up to 35% by 2030.

Matt Wheeldon, Wessex Water's director of infrastructure development, said: "We know our customers care passionately about protecting watercourses, whether or not they use them for swimming or recreation, and we share their passion.

"We would love to stop all storm overflow discharges immediately but unfortunately there is no quick fix – eliminating them completely would mean re-plumbing a sewerage system which has been built in this way for over 150 years.

"The solutions we're rolling out include separating out rainwater to stop it entering sewers and constructing large storage tanks to contain the combined rain and sewage for later treatment."

Wessex Water has developed an Artificial Intelligence (AI)-led app which predicts bacteria levels using other parameters that can be continuously obtained from sensors within bathing or recreational waters.

Mr Wheeldon added: "We've already used AI to provide real-time water quality information at Warleigh Weir, near Bath, Baltic Wharf in Bristol and in Poole Harbour where we are providing water quality forecasts for the shellfishery and recreational businesses."