Frequently Asked Questions

Dr Nick Everall, Director of independent ecology firm Aquascience Consultancy Limited, and ex-Principal Biologist at Severn Trent Water, analysed a sample taken from Windermere on 16 August 2022. The summary report is copied below which shows the presence of potentially toxic blooms on Windermere and explains their impact: 

"The levels recorded in the sample you sent exceeded both EA and WHO guidelines for levels of Anabaena (and Microcystis), where thresholds are set such that if the bloom were toxic there would be enough toxin to pose a risk to humans and other animals (e.g. dogs and cattle). Not all blooms are toxic but studies in the 80’s-90’s have shown that ~70% of tested blooms were. Testing for toxins costs around £400/sample and one would have to test daily as toxicity of blooms can switch back and forth within 24-hours. Precautionary Risk Assessment principles are applied based upon levels of the algae in cells/ml (WHO) and colonies/filaments/gyres/ml (EA). UK EA thresholds for signing a water body to warn public users are less than the WHO, probably because they sample standing waters very infrequently. The sample from Windermere failed both standards for Anabaena and Microcystis.

The levels recorded may or may not be typical of the whole water body and more samples would be required to verify that. Nonetheless, the area associated with the sample at least should be signed to warn public users.

On a weight for weight basis the neuro and hepato toxins potentially produced are as toxic as cobra venom.

For humans, unless drinking the water directly, the effects are likely to be diarohea and vomiting and skin rashes caused by a third group of compounds produced by blue-green algae called pepto-polysacharrides. If humans ingest enough algal laden water then hospitalisation and death can occur. A group of TA’s who drank directly from a blue-green algal lake in Staffs were hospitalised and some members of their party died. People on dialysis in Brazil, where water supply was not well treated, have also died and there are many more international records. Dogs and cattle frequently die from ingesting blue-green algal scums e.g. dogs cleaning their coats after swimming.

Root causes of blue-green algal blooms are often phosphorous levels in combination with raised water temperatures. Although some blue-greens, not Windermere identified ones this time, are fairly cold temperature tolerant and bloom under ice! They do not require nitrogen as they can fix this at the water-air interface a bit like terrestrial peas do from the air. 

Two consecutive (days-weeks apart) samples that show levels well below signing threshold are required before thinking about removing signs and should be based in combination with local expert knowledge on algal assemblages.”

Dr. Nick Everall FIFM C Env Reg UK Expert Witness (ex-Principal Biologist Severn Trent Water)"

Following an extensive bloom event, blue green algae dies and it sinks to the bed of the lake, where it begins to decompose. In this process it absorbs a lot of oxygen and, if a bloom is large enough, it can deplete enough oxygen in the water to kill fish and other wildlife.

The blue green algae also has the potential to produce toxins that can cause serious illness for both humans and animals if enough is ingested, and skin irritation if you come into contact with it.

The UK Centre for Ecology and Hydrology’s 2013 report titled: “Food web de-synchronization in England's largest lake: an assessment based on multiple phenological metrics” stated:

“Blooms of algae in freshwaters can produce potent toxins, potentially making water bodies unsafe for recreational activities and restricting their access to the public and their suitability as a source of water for drinking and irrigation.

Blooms are often produced by cyanobacteria, also known as blue-green algae. They typically colour the water bright green and can form a surface scum along shorelines. Cyanobacteria produce toxins which cause a range of health problems, from minor skin irritations to severe stomach upsets, and can even lead to death. The World Health Organisation has established guideline values of cyanotoxins and cyanobacterial cell densities for recreational use and for drinking waters.”

Blue green algae comes and goes, but as climate change continues to put pressure on our lake, the frequency of blooms will only increase. The first thing we would recommend is learning how to identify what a blue green algal bloom looks like to help you make an informed decision.

You can find more information on algal blooms here.

The Blue Cross offers advice to pet owners on algal blooms here.

You can see reports of algal blooms in Windermere using the UK Center for Ecology & Hydrology’s Bloomin’ Algae website and app here.

If you or your pet fall ill after making contact with blue-green algae, we suggest you seek urgently medical advice.

Windermere is under enormous pressures from excessive nutrient loading. This culminated last summer with the entire north basin of Windermere turning bright green due to a large cyanobacteria bloom.

The lake is not adaptable to the current climate crisis. We are going to see more rainfall in the winter months, which will increase the amount of discharges into the lake and we are under the threat of extensive droughts in the summer.

If we see a sustained period of drought, long enough to create a bloom that encompasses the entire lake, we could see a mass fish death in Windermere as have been seen elsewhere in the world:

River Oder, Germany/Poland
Mar Menor, Spain
Darling River, Australia
San Francisco Bay, USA
Béni-Haroun Reservoir, Algeria

Windermere in its natural state is an oligotrophic lake. This means that it would be so low in nutrient that algal blooms would not occur. The reason that algal blooms have occurred in the past in Windermere and the reason we see such severe algal blooms now is due to human input into the system.

United Utilities by their own admission are responsible for the largest input of nutrient into Windermere, so we feel it is safe to say that the largest contributor to the algal blooms is sewage pollution from their works.

The below statement from United Utilities’ 2013 Windermere Catchment Study suggests that they are aware of just how much they contribute to the algal blooms that occur on the lake:

"The analysis of the data shows that by removing all of United Utilities discharges there still will be algal blooms, but the severity will be greatly reduced to the point where they may not actually be visible.”
United Utilities Windermere Catchment Study, Final Report (November, 2013).

We understand that multiple factors have contributed to the lake's degradation, including climate change, septic tanks, and farmland runoff. However, the discharge of sewage into the lake by United Utilities is by far the most significant contributor (United Utilities works are the largest source of phosphorus input into the lake) - tackling this issue first will allow us to have the greatest impact before it’s too late for Windermere.

United Utilities and other groups often quote figures relating to source apportionment of total phosphorous in the lake, however, we do not recognise these figures as being accurate. The Environment Agency has confirmed that ‘“the source apportionment is a work in progress” in response to an EIR request submitted in December 2022.

We have not been provided with or seen data from septic tank inflow/outflow monitors, nor have we seen data to suggest that extensive catchment-wide sampling has been completed to look at diffuse soil addition. To us, this suggests that incomplete data sets are being used in modeling, which puts into question the validity of the models used.

There are 16 point sources of pollution in the catchment that are controlled, maintained and operated by United Utilities. Explore the map on our homepage to see the exact location of these and the number of hours that they spilled for in the last few years.

As all the rivers in the catchment ultimately flow into Windermere, all the treated and untreated discharges from these assets eventually end up in the lake.

We are not engineers or waste water treatment experts, however we have 3 case studies which highlight what is possible.

The first and most significant is Lake Annecy in France. Lake Annecy is similar to Windermere - it was formed by glaciers 18,000 years ago, it’s around 14 km long, it’s split into two distinctive basins, and it has a large population (130,000) living around its shores. The main difference between our lake and Annecy, is that Annecy is classed as the cleanest lake in Europe. In the 1960s, the impact of sewage on Annecy became clear. The lake saw increased algal blooms and declines in fish populations. Driven by a campaigning community, the mayor and local politicians, Annecy has been transformed. They have achieved this by investing €300M to channel their sewage to treatment plants outside of the lake's catchment.

The second case study is from closer to home. In the 2013 catchment report (which was used to inform United Utilities investment decisions for the 2015-2020 period), United Utilities modelled removal of what was then Windermere WwTW from discharging into the lake. They showed this was achievable by laying a pipe underneath the surface of the lake, with effluent finally discharging in the Leven estuary. This was costed at only £25 million, which in the context of United Utilities’ turnover and profits is a minimal investment.

Thirdly, we have Elterwater, which in the 1990s was classed as eutrophic. To allow Elterwater to recover, the Langdale treated effluent pipe was moved to below the lake, to prevent it from discharging into Elterwater. This demonstrates that removal of discharges from a lake within the catchment is achievable.

We believe that we need a set standard of treated effluent across the catchment. Outfalls should be channeled into pipes that take it to a large WwTW outside of the catchment, where it can then be discharged into to a body of water which has a dilution factor and is not a slow and enclosed ecosystem like Windermere.

The Environment Agency have consistently had their budgets cut by central government and are underfunded. We do not feel that they have the resources or the manpower to adequately regulate the waste water companies.

The water industry relies on operator self monitoring, but in our opinion self-regulating isn’t a good idea. It is a bit like marking your own homework!

No. 5,900 hours of raw sewage was discharged into the lake in 2022. However, treated sewage also contains phosphorus which contributes to the potentially toxic algae blooms.

In 2022, 5,900 hours of untreated sewage was discharged into the Lake. These figures were released by the Environment Agency on 31st March this year. Full data sets can be downloaded from the United Utilities website here (Google “United Utilities EDM”).

Storm overflows are designed to act as relief valves when the sewerage system is at risk of being overwhelmed, such as during heavy downpours when a lot of rainwater runs into drains and the sewerage system in a short space of time.

However, in 2022, United Utilities spilled raw sewage into the lake for over 5,900 hours.

In 2012, the European Court of Justice brought a case against the UK government over storm overflows. The Commission stated that untreated waste water was being discharged into the River Thames, even in moderate rainfall conditions, and that no immediate measure was foreseen to resolve that problem, which would therefore persist and even grow worse. The Court found that “the United Kingdom had failed to fulfil its obligations under the 1991 Urban Waste Water Treatment Directive”. It noted the requirement to collect & treat all waste water, except in the case of ‘exceptional or unforeseeable events’.

We have scientifically robust data, provided and analysed by Professor Peter Hammond BA MSc PhD MSc, which evidences illegal sewage spilling in the Windermere catchment in previous years. This was reported at Hawkshead Pumping Station, Ambleside WwTW and Near Sawrey WwTW.

Storm overflows are just a part of the problem. The standard of treated effluent across the catchment varies from site to site and United Utilities have stated that the treated effluent is a greater contributor of nutrient into the lake than the storm overflows (although the data behind this is unclear as they do not monitor the composition of discharges from storm overflows). Both the treated and untreated effluent contributes to the sediment build up at the bed of the lake and this is why Windermere, as a slow and enclosed system, is in such a critical state.

A 2020 research study from the Univeristy of Southampton’s Windermere Research Project, titled “Tracing lake pollution, eutrophication and partial recovery from the sediments of Windermere, UK, using geochemistry and sediment microfabrics” stated:

“Analysis of sediments from the last 200 years shows that Windermere underwent eutrophication due to increased human activity, leading to increased concentrations of potentially toxic elements in the lake sediment including lead, mercury and arsenic. Lake remediation schemes, including improvements in sewage treatment, have led to a partial recovery, but current climatic warming trends are contributing to renewed concentrations of toxic elements in the surface sediments (Fielding et al., 2020).”

The lake is made up of two large basins and the water doesn’t move in the same way as it does in a river or the sea. It takes a drop of rain water nine months to go from the North end of the lake to the South end. Much of the input into Windermere sinks to the bottom of the lake before it has a chance to wash out to sea. This is what makes Windermere unique and why it needs to be prioritised in the national conversation.

United Utilities is a £7 billion company. During their 2015-2020 investment period, they invested £40M into the catchment. In this same period, they returned £1.6 billion to investors.

The recent funding announced by the government, proposes an additional £19M for Windermere. This is still a proposal and we have not seen any firm plans or timescales to indicate where and when the money will be spent, other than a list of CSOs (Combined Storm Overflows) included in the initial proposal to Ofwat. This investment is only proposed to tackle storm overflows. It does not address the treated effluent, which is likely to be causing more damage than the untreated effluent and is also responsible for increasing nutrient levels in the lake. We believe that this investment should be spent on not only improving storm storage capacity, but also on improving the treatment processes to strip more nutrients from final treated effluent and to begin tackling the infiltration into the network, which would reduce the reliance on discharging sewage into our rivers. Much more funding is needed to make any real impact here and this £19M is only suggested to remove 39% of storm spilling.

Furthermore, the proposed £19M investment is not strictly an ‘additional’ investment. This is being brought forward from Price Review 25 and will be covered by the tax payer in the same way as regular investment plans in the 2025-2030 Price Review cycle. You can read more about how this accelerated funding will be administered in the Ofwat document here.

Ofwat already has the power to impose fines equivalent to 10% of a company’s annual turnover. These fines have only been enforced once in the past 30 years.. The system is there, but government and the regulator is simply not using it.

We have not been informed directly of United Utilities refuting any of our data. Our information pack, which is downloadable from our website, references each piece of information with a reputable source and/or data. If UU are accusing us of presenting inaccurate or misleading information, we would need clear evidence otherwise, in which case we would be happy to retract any information which we are told is incorrect. Our data requests to UU have been refused so we only present information we are able to gather from other verifiable sources.

We also partner with leading charities on sewage pollution, including WildFish and Windrush Against Sewage Pollution (WASP). These organisation employ leading scientists and have been collecting data for many years, using independently-verified scientific methods for collection and analysis.

Our invertebrate baseline sampling is carried out by an independent body and the samples are tested by a professional entomologist. Once volunteers are trained, there are control samples taken to be further analysed by a professional entomologist to ensure that there is quality control and that results are robust over several years.

Smart Rivers is the only citizen science project to receive professional analytic quality control, and as such is underwritten by the institute for fisheries management.

This sampling is allowing us to build a unique data set that can show the long-term impact that pollution is having on our waterways, something that isn’t achievable with point-in-time water quality testing such as the Big Windermere Survey.

It could take decades for the lake to return to its natural state, which is why United Utilities must stop discharging sewage into the catchment now. We have to start protecting it now for the future. If we protect Windermere now, the lake will begin to recover.

No. If all sewage discharges are removed from the lake it will begin to recover. This has been achieved in Lake Annecy in France. Sewage discharges were also removed from Elterwater when it was in a similar state to Windermere in the 1990s and it is slowly beginning to recover.

United Utilities hold an abstraction license to take drinking water from Windermere.

Yes! You should immediately report pollution events to the Environment Agency.

If you observe discolouration, odour, or other evidence of pollution at any of United Utilities sewage outfalls, or elsewhere in the catchment, please: 

Immediately report a water pollution incident to the Environment Agency on 0800 80 70 60 and ask them for an incident number.

Fill in the Save Windermere Sewage Outfall Reporting Form and upload a photo. We can then follow up on your case on your behalf.

Download our Sewage Event Reporting Information Pack which includes the precise locations of all United Utilities outfalls, along with instructions on what to do in case of a pollution incident.

You can save this information to the Notes app on you phone (iOS only) for easy access by clicking here.

Yes! If you see evidence of blue-green algae on Windermere, complete the form here, and upload a photo.

This data will help us to build a picture of the overall health of the lake and ensure appropriate guidance is in place for lake users.

You should report algal blooms and any water pollution incidents to the Environment Agency on 0800 80 70 60 and ask them for an incident number.

Finally, you can record blue-green algal blooms using the UK Center for Ecology & Hydrology’s Bloomin’ Algae app.

Yes! If you, or your pet, have fallen ill or suffered from an infection after swimming in Windermere, please complete the form here to register this with the campaign.

Data collected will be anonymised and will not be shared with any third parties. This data will help us to build a picture of the overall health of the lake and ensure appropriate guidance is in place for lake users.

The Save Windermere campaign is pro-tourism and business. The Lake is our biggest asset and we need to protect it in the long term for our businesses to continue to thrive.

In the short term there are two possible outcomes: If we get a severe algae bloom this year and someone (or their pet) gets ill or dies, the adverse publicity will drive tourists away. Alternatively, if we can obtain a commitment from government, the regulator and the water company that they will invest in Windermere and strive to make it the cleanest lake in Europe, our tourism industry and our businesses will continue to thrive and grow.

Tim Farron is fully supportive of the campaign and is actively asking questions in Parliament on our behalf. The campaign in in close contact with Tim and we regularly discuss the political aspects of the campaign.

The major stakeholders in the lake are the communities that live and work here. We are working with major hoteliers, local businesses, landowners and the community that call Windermere home, as well as with our charity partners and scientific experts.

We will work with anyone who believes that we need to end sewage discharges into Windermere, however, we are not willing to partner with a company that knowingly discharges sewage into the lake, has been proven to spill illegally and has failed to adequately invest in the catchment.

As a campaign, we do not receive any United Utilities or Government funding to ensure that we remain independent.

Save Windermere was founded by Matt Staniek.

Matt grew up in Windermere, studied Zoology at university, returned home - and then broke his neck in a car accident. He started his campaign in July 2021 after going to the head of Windermere each day for 3 years, whilst recovering both mentally and physically. In this time, he observed the natural world around him, and sadly, the sharp, sudden decline in our rivers and our lake.

Matt was appalled when he found out that sewage is being discharged into our lake and at that moment, decided to dedicate his life to solving this issue.

All money raised will go towards further monitoring of the lake (e.g. our invertebrate sampling super-hub), education and awareness programmes (incl. campaign films, promotional materials & community events), political lobbying, and legal advice, along with a modest salary for Matt's full-time advocacy. Save Windermere is a registered not-for-profit Community Interest Company (CIC), and is governed by a Board of Directors (Registered company: 14689574).

Our website savewindermere.com is the best place to find information on the state of Windermere.

You can also find us on Instagram @mattstaniek, Twitter @mattstaniek, or on our Facebook page - search ‘Save Windermere’.

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Report pollution events, algal blooms and swimming-related sickness.

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