WHY DO WE OBJECT
The Fight Against the “Thames Sewage Pump”
The Save Our Lands & River (SOLAR) campaign opposes Thames Water’s proposal to extract 75 million litres of fresh water daily from the Thames at Teddington and replace it with treated sewage effluent. While we recognize the urgent need for climate-resilient water solutions, we believe the TDRA scheme is a “low-quality, short-term fix” that prioritizes corporate savings over environmental safety. Our objection is based on the irreversible damage this project would cause to the river’s delicate ecosystem, the destruction of green spaces, and the industrialization of one of London’s most cherished green corridors.
We object because Thames Water Cannot be trusted with the environment
Thames Water continuously fails to raise its game to meet environmental targets and has not given any evidence that the river will not be harmed by TDRA.
"Whilst there is undoubtedly a need to future-proof our water supply, there is a fundamental issue around trust. Thames Water has a terrible record — regularly spilling raw sewage into our rivers and losing a quarter of its water supply every day due to leaks — whilst rewarding its executives with sky-high bonuses."
Munira Wilson, MP for Twickenham, Letter to Constituents, November 2023"
Read about the risks to the river of the planned TDRA treated effluent outfall ...
We object because TDRA is not a good solution for Londons future water needs
TDRA is a relatively small, fixed sized scheme. Given the need to plan now for evolving environmental standards, climate change and supply requirements TDRA does not appear to be a good solution to London’s future water needs.
Read more about TDRAs shortfalls as a suitable future proof scheme ...
We object because Thames Water cannot be trusted with customer money
Thames Water’s is in an Ofwat oversight regime because of financial problems which continue to this day. The costings presented by for TDRA seem to increase every year which for a short term fix does not seem a prudent investment.
Read more about concerns on Thames Water’s financial position and the rising costs of TDRA ...
We object because Thames Water have not shown that TDRA is the best value option
Despite the supposedly improved presentation in the Final WRMP24 the Best Value explanation for TDRA remains unclear. SOLAR has tried to understand how the best value plans are worked and we remain of the opinion that the justification for TDRA is weak and unclear
Read more about our assessment of Thames Water’s Best Value decision making ...
We object because of Thames Water’s failure to listen to customers.
Thames Water has consistently failed to demonstrate genuine transparency or accountability throughout the consultation process. Despite record-breaking levels of public opposition—including thousands of formal objections and multiple petitions—the company has largely ignored community concerns, opting instead for a "tick-box" approach to engagement.
Read about Thames Water’s continuing failure to listen and understand...
We Object because of Disruption to Neighbourhoods
There has been a real lack of information from Thames Water about how they will help customers directly affected by TDRA construction. From tunnelling works to traffic and noise and air quality in Mogden, Twickenham, Ham and Kingston all we have is that Thames Water may look at mitigation. For example, the Local roads in Twickenham, Ham, and Kingston are not built for the continuous heavy construction traffic required for this multi-year project, leading to severe noise, vibration, and air quality concerns for residents. No specific information on biodiversity or enhancements have been presented for any locations,, certainly not local to the impacts. Thames Water says all will be revealed in the DCO application. This is not the way to gain public trust.
Read more about some of the construction impacts of TDRA ...
We object because Thames Water Cannot be trusted with the environment
Thames Water performance on the environment -
In the 2025 EA environmental performance report of water and sewerage companies operating in England, Thames Water was given a one-star rating for 2024. Here is the Thames Water star ratings since 2021. (Water and sewerage companies in England: environmental performance report for 2024 - GOV.UK)
| Water Company | 2021 | 2022 | 2023 | 2024 |
| Thames Water | 2stars | 2 stars | 2 stars | 1 star |
This report also shows that in 2024, Thames Water had the most (523) of all pollution incidents, more than double the number of 2023. Of the 75 serious water pollution incidents that occurred, 33 were from Thames Water.
Thames Water and river water quality - Thames Water stated they do not plan to make the river worse with this scheme; "We’re committed to ensuring that water quality of the River Thames is not deteriorated as a result of the Project." (Thames Water, p.10 Teddington Direct River Abstraction and Water Recycling Project, October - December 2023.)
Despite this statement they did not produce the full range of water quality results from the Mogden tertiary treatment pilot plant at the statutory consultation and have not made clear that they will seek to remove a wide range of biological or chemical contaminants from the sewage treated in Mogden.
Even under the “no deterioration” description Thames Water will not be obliged to remove pharmaceuticals such as hormones, painkillers and antibiotics. They will also not be obliged to remove microplastics or emerging contaminants (also known as forever chemicals) like PFAs and PFOs. These are suspected as carcinogenic and derived from cleaning products and the manufacturing industry.
It should be noted that Thames Water are not proposing to align TDRA with proposed EU standards which would significantly increase protections from harmful discharges. TDRA does threaten to make us the dirty man of Europe.
Thames Water and environmental regulation – Thames Water often refers to the strong regulatory regime around the water industry eg the Environment Authority and DEFRA etc as part of its defence against causing harm. Campaigners are concerned that Thames Water is pushing ahead with TDRA knowing full well that the regulatory environment is changing, especially around forever chemicals and other contaminants. The Government Water White Paper published in 2026, the EA consultation on Significant Water Management Issues and Government proposals around PFAs all clearly highlight the harmful impacts of this kind of contamination and the need to consider how this can be managed in the future.
(A new vision for water: white paper - GOV.UK // Significant water management issues - Environment Agency - Citizen Space // PFAS Plan: building a safer future together - GOV.UK )
Constructing a new source of contamination on a site with limited adaptability flies in the face of common sense.
The impact of putting treated sewage into the River Thames
Impact on plant life of treated sewage in river water: The Environment Agency appears to be looking at 'nutrient neutrality' for the effluent outfall. This means controlling nutrients such as Nitrogen and Phosphorus, well known to gardeners as they're added to commercial compost and fertilisers in specific amounts to promote plant growth.
The presence of these in raw sewage damages aquatic plants, causing some species to thrive and become invasive and others to die, compounding the wider river ecosystem.
The Environment Agency is requiring Thames Water to limit these nutrients to appropriate levels. This is why Thames Water is saying the effluent outfall ‘will not make the river any more polluted.' This does not take account of the increasing range of contaminants that are in sewage these days.
Impact of chemicals in treated sewage in river water: Currently, the Environment Agency does not limit many of the chemicals that Thames Water can leave in treated sewage that is discharged into waterbodies.
Thames Water has confirmed they will not be removing pharmaceuticals such as hormones, painkillers and antibiotics. They will also not be removing microplastics or emerging contaminants (also known as forever chemicals) like PFAs and PFOs. These are suspected as carcinogenic and derived from cleaning products and the manufacturing industry.
Risk of faecal contamination by putting treated sewage in river water; Currently, Thames Water is not obliged to, and nor has it said it is planning to, remove bacteria, viruses and parasites from the effluent, which would include faecal contaminants such as E. coli, salmonella and coronavirus. The amount of treated sewage water flowing into the Thames when TDRA is active will be the equivalent of that which comes from the Hogsmill sewage treatment works upriver. The Hogsmill STW has tertiary treatment permit which does not require removal of faecal contaminants such as E. coli, salmonella and coronavirus.
The concentration of all these contaminants when the effluent outfall is flowing at 75 million litres a day will be greater because the abstraction plant will be removing 75 million litres of fresh river water a day and the river will be at its lowest due to drought. At this time river user numbers will be at their peak, especially children.
Swimmers at the proposed outfall location have sometimes suffered the effects of microbiological pollution from raw sewage spills. The effects of emerging contaminants on human and aquatic life are more and more a concern hence the proposed EU changes in sewage treatments.
Thermal load and salinity impacted by putting sewage in river water. The natural water temperature of a river is increased when treated effluent is added. Treated effluent is warmer than river water.
Increasing the temperature reduces dissolved oxygen and increases the metabolism of cool- and cold-water fish, causing them to burn energy at a faster rate and result in death when river temperature exceeds their physiological limits.
The salinity (salt content) is also increased when treated effluent is added. Salinity plays an important role too as it impacts growth rates and metabolism. For some fish higher salinity is beneficial but for others, it’s incredibly detrimental.
We object because TDRA is not a good solution for Londons future water needs
TDRA is a relatively small, fixed sized scheme. Given the need to plan now for evolving environmental standards, climate change and supply requirements TDRA does not appear to be a good solution to London’s future water needs. It is not adaptable to climate change and future changes in abstraction permits.
1.-At 75 megalitres per day (Ml/d) maximum capacity, TDRA will supply approximately 2% of the 2.6 billion litres of water supplied to London every day. Put that in the context that Thames Water loses 19% of supply to leaks every day. Remember also, TDRA is not a supply project. It is a drought only scheme, so in non-drought periods it will not contribute to London’s water supply.
2.-TDRA is a fixed size drought scheme. It cannot be scaled up in size and will not provide a general uplift in supply. If Thames Water was to try to use TDRA to take more water from the river and put back in more treated effluent than they have said OR if they used the scheme more often than now proposed it would cause the very environmental damage it is meant to avoid.
3-TDRA proposes Tertiary treatment of sewage before discharge. The focus of the proposed treatment is the removal / reduction of specific (and limited) chemicals eg phosphorus and nitrates to protect plant ecosystems. Tertiary treated effluent will still contain biological contaminants eg E Coli, microplastics, antibiotics and Contaminants of Emerging concern (CEC).
The Cunliffe Review (2024) explicitly recommended the UK consider adopting quaternary wastewater treatment standards to take account of the rising levels of biological and chemical contamination in sewage. The EU Urban Wastewater Treatment Directive (revised 2024) now mandates quaternary treatment for all wastewater treatment facilities by 2045 - just 12 years after TDRA's planned 2033 commissioning.
TDRA will mean paying for and being “locked in” to a sub-standard treatment almost from the time it is “switched on”. By 2045, this infrastructure will position the UK as having demonstrably lower wastewater standards than the EU. It may also fall short of evolving policy on treatment standards being developed by UK Gov on “forever chemicals”.
4-Climate change will mean low river flows in summer and flash winter flooding / heavy rainfall in winter. This will impact the river water quality and therefore the ability to abstract at TDRA. Changes in flow conditions, in combination with changes in use of the Thames Barrier, may impact the tidal reach of the Thames and increase the flood risk of the Teddington riverside location of the abstraction (intake) facility. These events could result in TDRA having to be “stop started” in a way that would undermine its reliability in drought.
We object because Thames Water cannot be trusted with customer money
Thames Water’s business performance - OFWAT’s October 2025 Water company performance report 2024-25 states that “Thames Water Is currently in our turnaround oversight regime …. It needs to deliver material improvements across multiple areas including leakage and internal sewer flooding….” They follow this up with “Our assessment of companies’ performance for 2024-25 …Thames Water … moved into the average category from the lagging behind category in 2023-24 but have …. dropped back into the lagging behind category in 2024-25. Thames Water has now been in this category for four years of the 2020-25 period …”.
Does that assessment describe a company that customers can trust with extra bill payments?
Thames Water – questions around TDRA Costs - SOLAR has considered Thames Water's stated costs for TDRA. These started somewhere at £325 million to build TDRA rising to £425 million when the change to a bigger tunnel was decided on. The price review in 2024 showed a TOTAL life cost of just shy of £1 billion.
SOLAR has looked at the figures provided by Thames Water to the PR24 and WRMP24. We consider that there may be a considerable under estimation of the total life costs. Allowing for real time interest changes over the next 7rl year for construction at 4.5%, per year, plus 2.5% interest per year for 80 years of operating costs plus financing costs SOLAR has estimated the real cost to customers could approach £2.5 billion in current terms.
TDRA will be utilised on average 6 weeks a year (12 to 16 weeks every 2 years). £2.5 billion is an extremely high cost for such an intermittently used scheme. There are alternatives and there are questions about how “future proof” TDRA will be.
Taken in context with the less than stellar performance review from Ofwat can we be confident that TDRA is the best use of customer money?
Thames Water has repeatedly put profits and shareholders ahead of customers and the environment. Prosecutions of Thames Water by the Environment Agency for pollution incidents have now led to fines of £35.7m between 2017 and 2023.
- Rivers polluted by "reckless" Thames Water (Environment Agency)
Judge - Thames Water "deliberately misled" the Environment Agency in and around pollution of rivers in Sussex and Surrey in which several thousand fish died. - Water companies given £114m performance fine – with Thames Water amongst the worst of the lot. (CityAm, September, 2023)
- Thames Water hit with £73m penalty over pollution and leakages (CityAM, November 2023
- Struggling Thames Water fined $4 million by UK court (Reuters, July 2023)
- Sewage in kitchens and ‘white elephant’ projects: why Thames Water is struggling (The Guardian, June 2023)
We object because there are questions about TDRA as the best value option
Thames Water claims to have assessed 1,400 schemes through their Best Value methodology before selecting TDRA. However, the Best Value process is very opaque. That this is true is demonstrated by the fact that in response to Thames Waters draft WRMP24 Ofwat specifically required Thames Water to clarify several aspects of how best value information was presented. ( Updated response to Defra’s request for further information 2024).
Despite the supposedly improved presentation in the Final WRMP24 the Best Value explanation remains unclear. SOLAR has tried to understand how the best value plans are worked and we remain of the opinion that the justification for TDRA is weak and unclear.
Amongst other things, Thames Waters “backchecking” process does not seem to have reevaluated previously dismissed schemes, Thames Water’s dismissal of alternative plans is not properly evidenced and their “option cost” analysis is weak.
We object because of Thames Water’s failure to listen to customers.
First – A FLAWED TDRA consultation process.
The scale of responses to the TDRA consultations raises serious questions about how well Thames Water engaged with the public. It demonstrates a lack of genuine responsiveness by Thames Water to what people are saying and a lack of transparency.
Some examples of lack of transparency in consultations:
-Key data on water quality and facility design was not available during the consultations; in March 2026 Thames Water indicated it was analysing the Pilot Plant results but made no commitment to make the results public.
-Consultations were framed only to solicit views on how TDRA would be built as opposed to if it should be constructed at all. Customers were not consulted on alternatives (eg, delay 2 years to develop more knowledge of Water Recycling or Water Transfer”).
-The consultation was very short on detail of designs for the abstraction structure and the kiosk in Burnell riverside which will have a significant impact on the area.
-Space constraints at Mogden for the Tertiary Treatment plant not discussed.
-There was little specific detail on how the impact works would be mitigated short and long term in terms of environmental improvement and impact on people.
The lack of transparency undermines the whole of the consultation process; the public and statutory consultees were asked to respond to the TDRA proposal without access to the evidence that would allow informed assessment of potential environmental harm or site impacts.
In 2025 the TDRA statutory consultation attracted 14,735 responses, more than ten times the typical rates for such consultations. The non statutory consultation in 2024 had nearly 7000 responses.
SOLAR considers that the vast majority of responses expressed opposition to TDRA. Clearly people were not convinced by Thames Waters publicity machine.
Second - FLAWED water resource management plan consultation - Draft WRMP24 in 2023
TDRA as a water resource option was part of WRMP24 (water resource management plan 2024.). A draft version of WRMP24 was consulted on in 2023.
In March 2023 in Ofwat’s response to the Thames Water draft WRMP24 they said: “…, it is not clear whether customers have been provided with enough information on proposed solutions (including alternatives and context) to draw conclusions and confirm their support.”
Only one Thames Water survey was undertaken that specifically examined public response to TDRA (amongst other aspects of the Draft WRMP24).
This survey was the Verve survey of May 2023. This survey used information from the draft WRMP24 consultation. The information about TDRA in the draft WRMP24 consultation was very limited and simplified, no alternatives were presented and the selection of TDRA was presented as the only solution to the impacts of severe drought in the South East and London, emphasising the possibilities of standpipes and water restrictions causing economic damage.
123 people took part in the Verve survey. Nearly 1600 people responded to the dWRMP24 consultation. Thames Water noted that a large amount of the consultation responses objected to TDRA. They noted that the “overwhelming” amount of the Verve respondents felt the benefits of TDRA outweigh local concerns.
Thames Water use the Verve survey to essentially dismiss the near 1600 people that responded to the consultations. There is an implication that “very engaged” people somehow do not represent the general population. Yet they are happy that 123 people informed by partial information in a survey are indeed representative of the Thames Water population.
To answer the Ofwat question, customers were not provided with sufficient and full information on the solution (in this case TDRA), on alternatives and there is every indication that there is no support for TDRA in particular.
We object because of disruption to neighbourhoods and environmental and social harms.
TDRA is Environmentally Flawed. There will be long-term environmental and ecological impacts on the River Thames water quality. There will be damage to green spaces in construction. There will be a negative change in the character of the "Arcadian Thames", an iconic and historic riverside area of the Thames around Teddington Weir.
- The plan will abstract (remove) water from the River Thames and replace it with treated effluent sewage at a unique location where the tidal river meets the freshwater river.
- There will be a significant impact to water quality from putting treated sewage into the River Thames. See details above.
Green spaces are protected for a reason: for the protection of nature and for the benefits that access to nature can have on human health. - Trees will be chopped down, Bat roosts and badger setts will be disturbed
- Building compounds will cause earth compaction and change the soil biome
- Building compounds will interfere with the natural movement of mammals and birds which may damage their ability to flourish.
- There will be air quality consequences from the significant increase in construction around Mogden arising from the change in tunnelling method.
"In addition to the potential traffic impact, it is likely the TDRA would have a substantial negative impact on the ecology of the Metropolitan Site of Special Interest for Nature Conservation that comprises Ham Lands. While I can acknowledge Thames Water’s stated commitment to biodiversity net gain and reconstruction, this does not discount the immediate impact the temporary destruction of acres of nature reserve would have on local flora and fauna. Once mature trees are felled, they cannot be replanted, and once badger setts are destroyed, and their occupants killed or driven off, they cannot necessarily be restored. These are two specific examples of the damage this project could do to the area, but Thames Water’s own documentation cites a potential impact on a wide array of wildlife."
Sarah Olney, MP for Richmond Park. Letter to Constituents, November 2023.
TDRA is Socially Flawed. To construct the tunnels, shaft, abstraction and outfall sites, Thames Water will be removing land from community use for a significant period of time, causing a high social cost.
Specifically in Ham Lands and Burnell Open Space:
- The Richmond / North Kingston construction areas will include tunnel shafts, the outfall and abstraction structures and the connection shaft to the TLT tunnel.
- Ham street car park / Ham Playing fields will see the construction of a 10.5 metre shaft at a constricted road junction which many people use to access the riverside. Construction of a shaft may take up to 8 months.
- Burnell Riverside Open space at the south of the scheme will be hoarded off for construction of the outfall structure, abstraction structure, as well as several ancillary kiosks. This could be for up to 21 months.
- Area wide - There are several primary and secondary schools within the area of construction; students, workers and thousands of residents will be impacted by construction traffic and restricted access to the riverside.
- Every day, there will also be a huge impact on the thousands of walkers, runners, casual river users and swimmers that use the Burnell Open space and the Thames Path National Trail towpath
Throughout residential neighbourhoods:
- Construction will take place on roads that were never built for, and cannot sustain, continuous heavy construction traffic of the kind TDRA will require. Some of the roads in Ham Lands can barely accommodate two cars at the same time.
- There will be issues of noise, air quality, building vibration, nighttime working, and construction traffic.
- The densely built areas of Isleworth will suffer from a large amount of HGVs and other construction traffic around the area needed to build the new treatment facility at Mogden. Added to this will be the “significant” increase in HGV traffic needed to remove tunnel spoil from the tunnel construction on the west side of the sewage works.
- The tunnels will be going under conservation areas with buildings that are already subject to subsidence. Many people in the areas of the conveyance route and the construction are very concerned about the impact of tunnelling under their houses and the sheer amount of construction traffic. These issues need to be addressed by Thames Water. There was no information for residents at the information events, despite Thames Water referring concerned residents to attend those meetings to get their questions answered.
Click to see the specific impact on Mogden and the new tertiary Treatment Plant and the new tertiary Treatment Plant, Burnell Riverside Open Space and Ham Riverside works area. To read more about this scheme in Thames Water's words, see their website here.
Swimmers at the proposed abstraction (removal) location on the river.
The Blue Tit swimmers in the River Thames.
The Blue Tit swimmers in the River Thames.
Link to a video walkthrough on Facebook of the areas that will be impacted by the TDRA on Burnell Open Space and Park Gate Woods. (Video courtesy of B O'Dea.)
Link to a video walkthrough on X / Twitter of the areas impacted by the TDRA on Park Gate Woods. (Video courtesy B O'Dea.)
Proposed outfall site near Burnell Open Space
Park runners in Burnell Open Space. Every weekend, around 350 Park Run participants join a 5K Park Run starting on Burnell Avenue and continue towards Teddington Lock along the tow path, returning back along the river and finishing at the YMCA Hawker Center. Under new TDRA plans this run would become impossible.
River from the Burnell Open Space
Every day, thousands of people use this stretch of the River Thames for recreation.
During the march against the TDRA in the summer of 2023, many joined our protest.
IN CONCLUSION
TDRA is poor value for money, has no convincing validation through the best value model, sets a low environmental bar, is a non-resilient and non-scalable asset, has operational risks that simply are not worth taking, is based on flawed and outdated customer research and shows a lack of any credible social and health impact assessment.
Since the initial 'Best Value' appraisal was carried out there have been significant changes to the TDRA proposals yet there has been no commitment to revisit the best value calculations.
Thames Water’s process has paid lip service to the many better and greener alternatives to solve the challenge identified.
You can rightly ask why if this is so bad is Thames Water pursuing it? We too have scratched our heads over this one. Our only conclusion is because it offers access to enhancement funding as a new asset and that means their regulatory assets go up and they can justify increased borrowing and charging the customer more.
Ham Lands from Maddy Shah Scott on Vimeo.
A film about Ham Lands
This video was created by local Kingston resident Maddy, a final-year student at Manchester University. She created this video as part of her university work. Her focus was to showcase the biodiversity and importance of Ham Lands and how destructive the Thames Water Teddington River Abstraction Scheme would be.
Learn how Ham Lands was created — on gravel pits filled with topsoil (and seeds) from all over London — and why it matters to save the area from any disruption.