What’s Really Happening at Esthwaite Lodge? Our Latest Sewage Investigation
Another day, another sewage story from Windermere. We're back with a new joint investigation from Save Windermere and Windrush Against Sewage Pollution (WASP), exposing yet more regulatory failings to protect our lake.
This time, we're zeroing in on a single site in Windermere - one we’ve only mentioned once before. That was when we called out the Environment Agency for having no idea how much sewage was spilling into a protected Lake District location.
Now, we’ve gone directly to United Utilities to request data from the site, something the Environment Agency still hasn’t done. This has allowed us to delve deeper into the potential environmental harm arising from the site which has been insufficiently monitored for over a decade.
Introduction
Esthwaite Lodge Pumping Station sits right on the shores of Esthwaite Water. It’s an in-network pumping station that passes sewage along the lake’s western shore to Hawkshead Wastewater Treatment Works (WwTW). Unlike Hawkshead Pumping Station, which functions as a combined sewer overflow (CSO), Esthwaite Lodge is classed only as an emergency overflow. This is a crucial distinction.
Figure 1: Environmental Permit for Esthwaite Lodge Pumping Station
Esthwaite Lodge’s discharge permit is crystal clear about when it’s allowed to release sewage. Discharges are only permitted in specific emergency situations, such as:
Electrical power failure not due to the act or default of the Consent Holder, its agents, representatives, officers, employees or servants;
Mechanical breakdown of duty, assist and standby pumps;
Rising main failure;
Blockage of the downstream sewer not due to the act or default of the Consent Holder, its agents, representatives, officers, employees or servants.
Critically, it cannot spill sewage as a result of rainfall. Although the permit is now 15 years out of date, United Utilities is still legally required to comply with its conditions. This is the only site that we know of around Windermere where discharges aren’t screened, meaning untreated sewage, including debris such as tampons, wet wipes, and other sanitary waste, can flow directly into the environment when the site discharges.
The Investigation
This brings us to the investigation. While reviewing the Environment Agency’s Compliance Assessment Reports (CARs), we were dismayed to see that although the EA had visited Esthwaite Lodge to check whether it was operating within its permit conditions, it failed to request any data that would actually enable them to verify this. The most recent CAR we received dates back to 2022, suggesting the Environment Agency did not visit the site in 2023 or 2024 and in Figure 2, you can see that the extent of this 2022 investigation into compliance at Esthwaite Lodge was inadequate.
Figure 2: Compliance Assessment Report (CAR) for Esthwaite Lodge Pumping Station from 2022
So, we asked for the Esthwaite Lodge permit, which the EA was not forthcoming with, and then decided to ask United Utilities for the data ourselves.
One of the first things that stood out is that the permit doesn’t require United Utilities to install Event Duration Monitors (EDMs) at this site. This is especially alarming given that Esthwaite Water is protected by some of the strictest environmental legislation due to its fragile ecology, being both a Site of Special Scientific Interest (SSSI) and a Ramsar site.
EDMs are an important tool that tell us more about when untreated sewage is being discharged. They’re fitted to sewage outfalls and provide three pieces of information:
When spills occur
How often they happen
How long they last
In the absence of EDM data, we had to get creative to identify potential instances of spilling, so we asked for wet well level data, flow data and telemetry data from the pumping station.
Telemetry data provides real-time information about what is happening at the site. For example, whether there is an emergency, if the site is spilling, how full the wet-well is or if an operator needs to attend.
Wet-well data indicates how much of the on-site storage capacity is being used. If levels are high and triggering a “spill” alarm, it suggests an increased likelihood that a spill is occurring.
Flow data measures how much sewage is being pumped from Esthwaite Lodge to Hawkshead Wastewater Treatment Works.
Data Refusal
Getting hold of data for Esthwaite Lodge was one of the most challenging data requests we've faced to date. United Utilities was anything but forthcoming and we had to pursue the full legal route to get access.
Our initial request was denied, so we submitted an internal review, laying out the legal obligations for disclosure. This was denied again.
We then escalated to the Information Commissioner, arguing that the data was clearly in the public interest. Only after the Commissioner intervened was United Utilities finally forced to release it.
You can find two examples of our ICO complaints and determinations relating to Esthwaite Lodge here and here.
Even then, it took months and United Utilities still refused to clarify the meaning of certain alarm codes, further obstructing transparency. This is despite UU claiming that they “welcome the opportunity” to discuss site specific data so that the correct assumptions are made.
Below is the timeline demonstrating their obstructive nature surrounding one of several data requests/clarifications we submitted during this investigation, each one met with resistance, delay or outright refusal.
19th July – We asked United Utilities a simple technical question about the telemetry data for Esthwaite Lodge:
“In relation to the telemetry data received for Esthwaite Lodge Pumping Station, I asked for clarity on the alarm code: NP1.NPS 1 Wet Well 1.Spill 1.LX_SPILL. Please could you tell me its function and interpretation?”
3, 5 & 12 September – We chased them repeatedly, as they had missed the 20-day statutory deadline under environmental information regulations.
16 September – United Utilities finally responded—refusing to answer. Their reason?
"Thank you for the below, and apologies for the delay. Your request for the technical meaning of the alarms does not fall within the definition of environmental information and has therefore not been reviewed as an Environmental Information Regulation request. However, this is with the business for review to provide you with the insight requested. We aim to have a response with you in the next couple of days. Thank you for your patience."
17 September – We requested an internal review and filed a formal complaint with the Information Commissioner.
18 September – 43 days after our initial request, we finally received an answer:
“This is an indicator of when the level within the wet well reaches a certain point, which could result in a spill from the permitted outfall. Please note that there is a large amount of erroneous data associated with this point (i.e. multiple entries logged for the same date/time), which shows false spills."
The Analysis
Once we finally obtained the data, we turned to Professor Peter Hammond of Windrush Against Sewage Pollution (WASP). This is where things got interesting.
Firstly, a reminder of who Professor Hammond is. He and Windrush Against Sewage Pollution (WASP) have done more than anyone in the country to expose the failings of the water industry. Peter’s landmark 2021 study, titled “Detection of Untreated Sewage Discharges to Watercourses Using Machine Learning”, revealed historic illegal sewage dumping as far back 2009. His work is so respected that, during an Environmental Audit Committee hearing, MPs acknowledged that his findings surpassed even those of the Environment Agency, the regulator responsible for spotting these spills.
Peter began by removing clearly erroneous data. Across the five-year period we requested, 8 August 2019 to 8 January 2024, there were 90,286 telemetry messages. The alarm code “South Lakes Lancs-Leven.Esthwaite Lodge.NP1.NPS 1 Wet Well 1.Spill 1.LX_SPILL” accounted for 98.28% of them.
Peter concluded that there was clearly an over-sensitive or 'trigger-happy' sensor at the site, prompting him to reassess what should be included or excluded in the analysis.
To clean the dataset, he excluded alarm signals that triggered and cleared within a few seconds. These short bursts that were likely false positives so instead he focused on longer-duration events that suggested genuine activity.
Figure 3: 2023 flow, wet well level and rainfall at Esthwaite Lodge Pumping station mapped against wet well alarm triggers.
Next, Peter cross-referenced those events with wet-well level data, flow rates and rainfall. That’s when clear patterns began to emerge, leading to charts like the one shown in Figure 3.
As shown in United Utilities’ own data, the chart clearly illustrates multiple instances where heavy rainfall leads to the wet well filling up, seen as visible spikes in the brown line. In several of these cases, the alarm is triggered. This is the same alarm that United Utilities describes as “an indicator of when the level within the wet well reaches a certain point, which could result in a spill from the permitted outfall.”
We believe it is in these instances that spills may have occurred.
This wasn’t just an issue in 2023. As shown in the tables in Figure 4, this has been happening over a number of years, with a curious gap in United Utilities’ reporting to the EA from 2018 to 2024.
Figure 4: (a) UU reported spills to the Environment Agency 2013-2024 (note, no spills were reported from 2018-2024). (b) Save Windermere and WASP analysis of UU data, demonstrating likely spill events between 2020 and 2024, apparently unreported.
We obtained the data from United Utilities covering 2020 to the start of 2024 and, in the second table, prepared by Professor Hammond, have highlighted what we believe to be instances when a spill could have occurred. As far as we can tell, none of these incidents, have been reported to the Environment Agency. Something curious to note here is that, between 2013 and 2017, data obtained via the EA’s WIMS portal shows reported spilling from the site. Why did the site suddenly seem to stop spilling?
Crucially, a point that we must reiterate here, rainfall alone is not a valid reason for this overflow to be used. The discharge permit is explicit: emergency overflows are only permitted under specific failure conditions. The fact that alarm signals are coinciding with rainfall events raises serious concerns that this site may be operating as an unpermitted storm overflow, which would be illegal.
And the frequency of these events is far higher than what we’d expect from an emergency-only overflow. That raises serious questions about how this site is being operated, and whether it's breaching its permit conditions. As ever, United Utilities are claiming these spill events didn’t happen, but we aren’t satisfied.
United Utilities said:
In July 2024, “….it was discovered that the ultrasonic sensor was originally set to read a maximum of 5.5 metres, whereas the pumping station did not spill until levels exceeded this threshold at 5.64 metres. Consequently, the sensor’s span was adjusted, and the ultrasonic sensor was utilised to configure the spill alarm.”
Firstly, we don’t think its a coincidence that they started looking at the site in July of 2024 at the very same time we started asking for clarity on their data from the pumping station. As ever with United Utilities, it's not what they say - it's what they don't say that always intrigues us.
To give a bit more context, let's refer back to the permit for the site, and a specific reference made regarding telemetry collection for the pumping station:
“(a) A 24-hour response telemetry alarm system shall be provided and maintained to give notification of failure or breakdown of the pumping station.
(b) The Consent Holder shall take all reasonable remedial measures to return the pumping station to normal operation as soon as practicable after receipt of warning of failure or breakdown of the pumping station.”
UU claims that until July 2024, a pear float was used to detect potential spills at the pumping station, which they say proved to be unreliable. Unreliable because in 2024 they ‘discovered’ that the ultrasonic sensor was originally set to read a maximum of 5.5 metres, but the pumping station did not spill until levels exceeded 5.64 metres. The EA has confirmed, in their 2022 Compliance Assessment Report (CAR), that the site has “a back-up float provided in the event of a failure of the level alarm system.” This seems to confirm that United Utilities should never have relied solely on the float to detect whether the site was spilling and that the level alarm system is intended to be the primary device used to monitor the site.
Let’s break this down.
Firstly, the permit at this site has been in place since 2010, so they are essentially saying that for 14 years they did not have a sufficiently appropriate telemetry system in place to provide notification of failure or breakdown of the pumping station. Does this mean they were unaware that it was not collecting the necessary information to confirm the site wasn’t spilling or did they know, and simply failed to act? And why does there seem to be evidence of spilling reported 2013 - 2017?
Secondly, they state that the sensor was set to a maximum read of 5.5 metres. This doesn’t mean the wet well didn’t exceed this level, it simply means it was incapable of reading above it. That’s a very important distinction.
Finally, if the information was definitely inaccurate, can they demonstrate that they were appropriately responding to alarm signals coming from the pumping station for example, by attending the site and collecting on-the-ground evidence that showed it wasn’t spilling? Or did they see alarms being triggered at the site and simply not attend when it was potentially illegally spilling?
This, we feel, leaves us with only two potential scenarios:
Were they negligent/incompetent - or was it deliberate?
Further questions we need answers to:
Can United Utilities definitively demonstrate that a spill did not occur at Esthwaite Lodge when the telemetry alarm was triggered by providing on the ground evidence?
If United Utilities claims these events did not result in sewage spills, then they must provide clear evidence that they were physically on site and actively investigating the alarm signals indicating a discharge from the emergency overflow. This includes: attending the location promptly, inspecting the outfall directly AND looking for visible signs of sewage debris or pollution. Simply asserting that a spill did not occur, without visiting the site or carrying out a proper inspection, is not a credible or acceptable justification. Did United Utilities take these steps?
United Utilities claims they investigated a faulty level sensor in 2024 that was providing incorrect data. But if this is true, why did it take them until then to realise it? Does this mean they ignored years of alarm signals that said the site was spilling?
United Utilities is required to notify the Environment Agency in writing of any known or planned introduction, material change or other substance likely to have a significant impact on the receiving waters. Has United Utilities ever notified the EA of any such impact?
When a discharge results in visible solid matter in the receiving waters or on the surrounding banks, United Utilities is obligated to take all reasonable steps to collect and remove the material as soon as reasonably practicable. Has United Utilities ever undertaken such a cleanup at Esthwaite?
Further to Question 4, Professor Hammond uncovered a revealing exchange in the House of Lords involving Lord Douglas-Miller, then Parliamentary Under Secretary of State at DEFRA, which seems to have been triggered by our last news article on the site in March 2024. When asked directly how often sewage had been discharged into Esthwaite Water from Esthwaite Lodge Pumping Station, his response was:
“The Environment Agency has not had any reports from United Utilities of emergency overflow discharges from Esthwaite Lodge Pumping Station.”
This statement raises yet more serious concerns about transparency, compliance and regulatory oversight at a site discharging into one of the Lake District’s most environmentally sensitive waters. Additionally, there are examples of United Utilities reporting spills to the Environment Agency up until 2017 so it is simply not true that this evidence doesn’t exist?
There is another part of this we have not yet addressed - what has the Environment Agency (EA) been doing?
We have several concerns regarding the EA’s lack of action at this site. One major issue is that the permit, which dates back to 2010, does not require United Utilities to have an Event Duration Monitor (EDM) in place - a device that would have clearly indicated whether or not the site had been spilling and left no ambiguity for UU to wiggle around.
However, one of the most pressing concerns for us is that the EA has visited the site to inspect its permit compliance, yet has never requested the data necessary to actually assess what has been happening. As far as we can tell, we are the first independent party to A) ask for the data and B) assess whether the site is compliant.
Why has the EA not asked for data to see if this site is spilling when it shouldn't be?
Why has the EA not noticed this?
What We Want to See
The first and most urgent intervention we want to see is simple: the Environment Agency must review the outdated permit for Esthwaite Lodge and require proper monitoring. This includes not only the installation of an Event Duration Monitor (EDM), but also a flow meter on the outfall into the lake, to measure exactly how much sewage is being discharged into the environment. This could reasonably be achieved by the end of the year. Emergency overflow permits are relatively straightforward, as they are not intended to allow frequent spilling. The EA could amend this permit to include additional monitoring and require United Utilities to comply with the new conditions by year-end. To demonstrate how simple this could be, we’ve drafted the wording for them to insert into the permit:
Under General Condition — Recording and reporting
6.(C) For the activity referenced in condition 1.(a), an event duration monitoring system and telemetry system shall be installed and maintained, as far as reasonably practicable, so as to give the operator data available of discharge occurrence (start and stop) at the frequency of whenever a spill starts and stops.
6.(D) For the activity referenced in condition 1.(a), independently accredited MCERT flow meters shall be installed and maintained, as far as reasonably practicable, so as to give the operator data available of discharge volume (litres per second) at the frequency of whenever a spill starts and stops.
See how easy this can all be? Why does the regulator continuously drag its feet?
We also expect the Environment Agency to investigate these potential spills as breaches of permit into a Site of Special Scientific Interest (SSSI) and RAMSAR-protected site.
Once again, we have to ask the question: What exactly is the EA doing if it isn’t properly scrutinising United Utilities and ensuring they are not polluting our lake? The Environment Agency must stop turning a blind eye to outdated permits, missing data and unchecked discharges into protected waters. Why is there no professional curiosity in the Cumbria and Lancashire EA? This is why we have called for a public inquiry into the regions regulator.
Crucially, the site needs to be future-proofed, so we are calling for increased on-site storage capacity and connection to a wider sewage network that diverts effluent away from Windermere entirely.
If this can be allowed happen at a SSSI and RAMSAR site in the heart of the Lake District National Park, it can and will be happening all over the country.
