Frequently Asked Questions

The already approved Havant Thicket Reservoir project, and the proposed water recycling scheme if it goes ahead, will be paid for by Southern Water, through its drinking water customer bills. These costs will be spread over many years – to reflect the continued benefits of the reservoir.

•    Portsmouth Water customers are not paying for the reservoir project through their drinking water or wastewater bills.

•    This applies for both the already approved reservoir scheme and should the additional water recycling proposals be implemented.

We’re a community-orientated company and pride ourselves on doing the right thing. This includes helping our neighbour to supply its customers with water, so it can reduce what it takes from the River Test and River Itchen, helping protect these rare and sensitive environments.

Water is scarce in the South-East, with the region officially classed by the Environment Agency as ‘water stressed’. Yet the impacts of climate change and population growth are increasing, and there is a need to leave more water in the environment to benefit nature. 

Southern Water has agreed to take significantly less water from world-renowned chalk streams, the River Test and the River Itchen in Hampshire. This will leave the company with a daily shortfall of more than 160 million litres of water in its Hampshire supply area, in the event of prolonged dry weather. 

We are in a position to help with a solution to this major challenge. This is because of the large number of natural springs in the Havant area which provide 30 per cent of the water we supply to our customers. These springs deliver a high quality, sustainable supply of water all year round and are thought to be the largest individual source of spring water in Europe.

Already approved reservoir scheme

- We’re fortunate to have more water than we need at certain times of the year. In the winter, and during periods of high rainfall, there is a surplus of water from the springs in the Havant area, over and above what we need for our customers. This surplus currently flows straight out to sea. 

- We can make better use of this surplus water by storing it in Havant Thicket Reservoir in Havant, which we are building and will operate. The reservoir will enable us to provide up to 21 million litres of water a day to Southern Water, when needed.

- We received planning permission for the reservoir project, as described above, in late 2021.

Water recycling proposals

- However, even if we transfer 21 million litres of water per day to Southern Water, they will still be left with a significant deficit and another solution is needed.

- As a result, proposals to add purified recycled water to the reservoir, to supplement water levels, are being developed, with further public consultation on these having taken place from 29 May to 23 July 2024(External link).

- The proposals are known as the Hampshire Water Transfer and Water Recycling Project.

- If approved to go ahead, the water recycling proposals would mean Havant Thicket Reservoir could supply a further 90 million litres of water a day to Southern Water.

- Recycled water is purified water, which in most respects would be cleaner than the spring water feeding into the reservoir. 

- Water recycling schemes provide a safe source of drinking water, according to the Drinking Water Inspectorate, the independent regulator for drinking water quality standards in England and Wales. You can find out more at: www.dwi.gov.uk/water-recycling.

- The Environment Agency has also issued a position statement, which recognises the need for water recycling as part of a diverse range of supply and demand options to secure resilient water supplies for the future.

With the exception of rainfall that naturally flows in from surrounding land, we will be in control of the reservoir, including any water that enters or leaves it. That’s for both the already approved scheme and should the water recycling proposals go ahead.

• We already closely monitor and analyse water quality at our existing operational sites and the same would be the case for Havant Thicket Reservoir. 
• Any issues with water quality would be quickly identified and the system would be shut down if needed – in line with requirements from industry regulators.

Once the reservoir is built and the surplus water from Bedhampton and Havant springs is put to good use, the only additional sustainable sources of water available in the South-East, based on our current knowledge, are desalinated seawater and treated wastewater. 

Water recycling compares very favourably with desalination, with regards to carbon emissions and energy consumption. Further information on the energy requirements for the water recycling scheme was published as part of Southern Water’s 29 May to 23 July 2024 statutory public consultation. 

The Environment Agency has also issued a position statement, which recognises the need for water recycling as part of a diverse range of supply and demand options to secure resilient water supplies for the future.

Desalination

• In 2020 and 2021, Southern Water carried out an extensive options appraisal process to confirm whether the desalination proposal was the right solution to develop further in the context of the other options available. 
• For the desalination proposal, it confirmed that it would likely have adverse impacts on the protected marine environment of the Solent and on the New Forest National Park, both from its construction and operation. 
• Out of all of the options considered, desalination at Fawley emerged from the options appraisal process as the least preferable option. The likely impacts of the plant and its associated pipelines meant that the proposal was not considered to be deliverable in this location, particularly in light of the better alternatives that were available.
• At the same time, Southern Water’s options appraisal process confirmed a combined option, involving both water transfer and water recycling solutions - the Hampshire Water Transfer and Water Recycling Project - as the most preferable option. 
• This option performed well across the range of criteria, especially when environmental impacts were considered.

Aquifer storage and recovery

• Southern Water has investigated other options including aquifer storage and recovery. This is when treated water is pumped into an aquifer, when surplus water is available, where it is stored and subsequently abstracted during a drought. 
• For this to work, the aquifer has to be “confined” –  as if water were stored in a big underground tank, where it’s one underground body of water and the water would remain in place and not flow away. 
• There are plans for one such Southern Water scheme in the Lower Test (where the chalk is ‘confined’ by the surrounding London Clay), but it can only provide about 5.5 million litres of water a day, less than 3% of Southern’s total requirement for Hampshire and very much less than the water transfer and water recycling option at Havant Thicket Reservoir.
• We also explored the option of aquifer storage and recovery.
• Our geology presents two possibilities for the creation of these: within confined chalk and within confined greensand. 
• Unfortunately, both of these options present significant challenges. 
• Our studies to date have shown the confined chalk in our supply region is either unproductive, or has karstic features (irregular limestone with sinkholes, underground streams, and caverns) allowing rapid flows, so any water that’s injected will be very difficult to store, as the water will be rapidly lost to the sea. The confined Lower Greensand is hundreds of metres deep and, therefore, boreholes would be very expensive, and we might find that it is unproductive and / or has water quality issues.
• As we enter our next round of water resource planning in a few years’ time, we do plan to review all our feasibility work to date, as well as consider new options, such as moving locations where we take water from to lower down river catchments.

We were consistently open and upfront about these proposals during our original planning application process, answering questions as best we could with the limited information available at the time. 

• Information was shared about water recycling during the planning process for the original Havant Thicket Reservoir scheme. During one of the Planning Committee hearings, elected members raised questions about the scheme and it was highlighted that any changes to the project set out in the original application would require separate planning approval in their own right, as is still the case.
• Much information was also publicised ahead of both Planning Committee meetings through Southern Water’s consultation on its desalination proposals which ran from February to April 2021 – you can read the consultation feedback report by clicking here(External link). 
• Southern Water's submissions to its regulators in both 2020 and 2021 (Gate 1 and Gate 2 respectively) confirmed its investigation of alternative options for both water recycling and water transfers involving Havant Thicket Reservoir. 
• A further non-statutory consultation on the water recycling proposals(External link) was also held by Southern Water in Summer 2022.
• This was followed by a statutory consultation that took place from 29 May to 23 July 2024(External link).

As with all of our water sources, any water from Havant Thicket Reservoir would be treated to meet strict drinking water standards before being supplied to customers.

In normal conditions, there would be no change to our current arrangements for supply of water to our customers. 

Our Farlington Water Treatment Works would receive water directly from Bedhampton and Havant springs. The reservoir would not be used to supply Portsmouth Water customers on a routine basis.  

Under the already approved reservoir scheme, during a drought, spring water stored in the reservoir would be used to supply Portsmouth Water customers, primarily in the Havant and Portsmouth area. This will allow us to share water from our network further west with Southern Water.

Given this arrangement, if the Hampshire Water Transfer and Water Recycling Project is implemented, Portsmouth Water customers would receive a mixture of spring water and recycled water from Havant Thicket Reservoir in drought and emergency conditions – such as, if we, or Southern Water, were not able to use our regular sources of water due to an engineering or other issue. For example, the loss of a treatment works because of technical problems, or damage to a trunk water main that supplies many customers. 

Like all UK water companies, we are required to plan for a number of different future scenarios, which take into account changes to population levels, climate change and the need to leave more water in the environment, to benefit nature. In some of these scenarios, recycled water could be used more frequently as a source for Portsmouth Water customers from 2040 and beyond. More information can be found in our Water Resources Management Plan for 2025 onwards(External link). It’s available on our website at: https://www.portsmouthwater.co.uk/news/publications/water-resources-planning/.

Already approved reservoir scheme

- In the winter, and during periods of high rainfall, there is a surplus of water from the springs in the Havant area, over and above what we need for our customers. This surplus currently flows straight out to sea. 

- We can make better use of this excess water by storing it in Havant Thicket Reservoir in Havant, which we are building and will operate.

- The reservoir will enable us to provide up to 21 million litres of water a day to Southern Water, when needed, during a period of drought.

- When needed during a drought, water from the reservoir will be treated at our Farlington Water Treatment Works to supply Portsmouth Water customers, primarily in the Havant and Portsmouth areas. This will allow us to share water from our network further west with Southern Water.

Water recycling proposals 

- If the water recycling proposals go ahead, some of the fully treated wastewater from Southern Water’s Budds Farm works in Havant would be further purified at a new (Southern Water) water recycling plant that’s proposed to be located south of Havant. The recycled water would then be transferred into Havant Thicket Reservoir to supplement the spring water already in it.

- Based on this, Portsmouth Water customers would receive a mixture of spring water and recycled water from Havant Thicket Reservoir in drought and emergency conditions – for example, if we were not able to use our regular sources of water due to an engineering or other issue.

- At all other times, the situation would remain as it is today, with people’s water supplies coming directly from the Bedhampton Springs, via our Farlington Water Treatment Works. 

- As with all of our water sources, any water from Havant Thicket Reservoir would be treated to meet strict drinking water standards before being supplied to customers.

- We are very conscious of concerns about potential changes in taste to drinking water, and we are assessing this aspect as part of our ongoing work. 

- We anticipate that there will be no noticeable change in taste due to the introduction of recycled water into Havant Thicket Reservoir, compared to the already approved reservoir scheme. 

- Regardless of the source of water that goes into the reservoir, the reservoir will be a surface water source which inevitably has distinctive characteristics from the springs, which are underground sources. 

- For these reasons, a change in taste compared to the spring water may be perceived during those events (extreme drought or emergency) where the reservoir is used to supply our customers. 

- Should this be the case, then there are options we can potentially implement at the treatment stage, such as the use of activated carbon to help resolve any change in taste. 

- Our research shows that 7 out 10 Portsmouth Water customers support water recycling as a way forward, and would be happy to drink recycled water.

- Like all UK water companies, we are required to plan for a number of different future scenarios, which take into account changes to population levels, climate change and the need to leave more water in the environment, to benefit nature. 

- In some of these scenarios, recycled water could be used more frequently as a source for Portsmouth Water customers from 2040 and beyond.

The water recycling process would be completely separate from stormwater releases, which only occur when a wastewater treatment plant and / or the sewer network are running at full capacity and cannot cope with the much increased levels of wastewater coming through the system during very wet weather. 

• Portsmouth Water is a drinking water only company, and Southern Water manages wastewater within our supply area at treatment facilities such as Budds Farm in Havant, Southern’s largest wastewater treatment works. Treated wastewater from Budds Farm is released out to sea, in line with the works’ operating licence.
• Wastewater treatment plants are regulated by the Environment Agency, which sets the standards by which they operate, both in dry and wet weather conditions.  
• In periods of heavy rain, both sewage and rainwater are collected in ‘combined’ sewers, which transport this mixed water, known as stormwater, to a treatment plant. Once the plant’s main treatment process is at maximum capacity and its stormwater storage tanks are full, heavily diluted, untreated stormwater must be released, either into the sea or a river or stream, to prevent flooding of homes, businesses and other properties. 
• Such stormwater releases are permitted under the operating licences granted by the Environment Agency, in the interests of protecting populated areas from flooding.
• Stormwater could never end up in Havant Thicket Reservoir or the drinking water network because the proposed water recycling plant in Havant would take its water feed from the end of the complete wastewater treatment process and not from any stormwater tank or overflow.
• The fully treated wastewater would then be passed through a further series of water recycling treatment processes, including reverse osmosis, where membranes with perforations more than 50,000 times smaller than the width of a human hair are used to filter out dissolved impurities.  
• Recycled water is highly treated, purified water and would be cleaner than the spring water feeding into Havant Thicket Reservoir.  
• For example, initial modelling indicates that the average concentration of nitrates in the recycled water put into the reservoir would be significantly lower than the levels found in the spring water – 0.1mg/l (milligrams per litre) in recycled water, compared to 30mg/l in Havant spring water and 34mg/l in the water from Bedhampton springs.
• Portsmouth Water is expected to be in sole control of the water entering and leaving the reservoir. 
• We already continuously monitor the quality of water at all of our sites with data automatically captured, analysed and checked in real time to ensure that we maintain excellent water quality that complies with regulatory standards.  
• The same methods and control systems would apply to the water recycling plant.  
• If there were any issues with the quality of the water being produced at the water recycling plant, the control system would automatically shut the plant down, making sure that water which did not meet the required standards would not enter the reservoir.

Customers and stakeholders have plenty of opportunity to learn more about the developing water recycling plans and have their say on them, such as via the public consultation held from 29 May to 23 July 2024(External link).

The consultation focused on those communities which would be potentially impacted by the construction and operation of the new infrastructure required for the Hampshire Water Transfer and Water Recycling Project.

Southern Water consulted to gather feedback on planning issues, such as the need for the scheme, the buildings and pipeline it wants to construct, and the scheme’s environmental impact. A Preliminary Environmental Information Report was published as part of the consultation.

As a development of major significance, Southern Water is seeking planning approval for the Hampshire Water Transfer and Water Recycling Project in the form of a Development Consent Order (DCO), following the Government authorising this way forward. 

Under the DCO, the final decision on the water recycling proposals would be made by the Secretary of State for the Environment, rather than by local planning authorities.

The DCO process puts an emphasis on early engagement with communities and stakeholders, allowing them to influence a project, including resolving any issues, before an application is made. 

• There is ongoing engagement with key stakeholders, local authorities and other statutory bodies on the Hampshire Water Transfer and Water Recycling Project. 
• This follows the consultation conducted by Southern Water on the scheme in Summer 2022, with continuing discussions with a range of local stakeholders having taken place since late 2020, including members of our long-standing Havant Thicket Reservoir Stakeholder Advisory Group.
• The water recycling scheme forms part of both our and Southern Water’s long-term Water Resources Management Plans, with our respective draft plans published for consultation from November 2022 to February 2023. Southern Water will also be holding a further consultation on its updated water resources plan during 2024.
• Development Consent Order (DCO) applications are submitted for large-scale infrastructure developments, categorised as Nationally Significant Infrastructure Projects. Such applications are made to the Planning Inspectorate which will consider each of them and make a recommendation to the relevant Secretary of State, who then decides whether to approve or reject an application.
• The consultation and engagement process involved via DCO will be just as rigorous, if not more so, than if the application went via the Town and Country Planning Act route.
• For example, the DCO process includes a stronger requirement for consultation and engagement compared to the Town and Country Planning regime, where decisions are made by local planning authorities. 
• It’s also important to note that local planning authorities continue to have a key role in the DCO process, not only acting as key consultees throughout, with opportunities to submit representations and appear at examination hearings, but also regularly being involved in detailed design matters and other requirements (like planning conditions).
• The DCO route is suited to the geographic scale of the Hampshire Water Transfer and Water Recycling Project and provides a streamlined single authorisation process for securing all the permissions, consents, licences and statutory powers needed to deliver this complex project in a timely manner.
• Under the Town and Country Planning Act route, the scale and complexity of the scheme means that multiple applications for planning permissions would need to be made to potentially six different local planning authorities, along with separate applications for a multitude of other consents and licences. The risks involved in the separate consideration of all of these applications could lead to considerable delays in delivery of the project and the benefits it will bring.

We continue to take a proactive approach and speak directly to our customers about recycled water. We are providing them with the facts, and offering opportunities to ask questions and give their views. 

We’ve already been using a range of channels and methods to communicate with local residents about Havant Thicket Reservoir, including drop-in events, community talks, newspaper articles, social media, leaflets and newsletters.  

We are going to build on this to make sure all our customers can learn about these water recycling proposals, ask us questions and tell us what they think.

We appreciate and understand that some of our customers and stakeholders have questions and concerns about the water recycling proposals, including drinking recycled water. 

We will also continue our discussions with our stakeholders, having already provided them with a great deal of information and opportunities to learn more – such as taking part in tours of the pilot water recycling plant set up at Southern Water’s Budds Farm treatment site in Havant, to test the water recycling technology being considered. 

We have always had a close, trusting relationship with our customers and stakeholders, and we will share the information they need to feel confident that recycled water is a safe, sustainable source of drinking water. 

It will cost about £340 million to plan, build and fill the reservoir with water.

The reservoir’s construction has been enabled by funding from Portsmouth Water's shareholder, infrastructure investor Ancala, and financing from leading banks. This includes funding from the UK’s National Wealth Fund – marking its first investment in the water sector.

Ultimately, the scheme will be paid for by payments from Southern Water to purchase the water it needs to supply its customers. Southern Water has considered a number of options to supply water to its customers and the reservoir is considered to be good value.

Only Southern Water customers who receive drinking water supplies from them will have the cost of the reservoir reflected in their bills. So, this does not include our customers who receive drinking water from us and wastewater services from Southern Water.