Frequently Asked Questions

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 is available as part of Southern Water’s 29 May to 23 July 2024 statutory public consultation. 

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’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 taking place from 29 May to 23 July 2024.
• 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.

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.

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 revised draft Water Resources Management Plan for 2025 onwards. 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 will have plenty of opportunity to learn more about the developing water recycling plans and have their say on them, including via a public consultation in from 29 May to 23 July 2024.

The consultation is being 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 is consulting 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 is being 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 anticipate there would be no impact on the environment at the reservoir, including the wetland, or its role as a new green leisure hub, if the water recycling scheme was to go ahead.   

Although further analysis and assessments are required, initial studies suggest that the purified recycled water entering the reservoir would be cleaner, in most respects, than the spring water that would be used to fill it. 

We will ensure that all the environmental and recreational commitments made in the original plans for Havant Thicket Reservoir, and which received formal planning permission in 2021, are maintained if the Hampshire Water Transfer and Water Recycling Project proposals were to go ahead. This includes delivering an overall environmental ‘net gain’ through the original reservoir scheme.

Environment

• Should the water recycling proposals be implemented, spring water would continue to be captured in the reservoir, in line with the original plans for the scheme. There would also be a daily flow of recycled water into the reservoir and an equal daily flow of water from the reservoir directly to Southern Water’s water supply works near Winchester.
• Water recycling is a well-established and widely-used water treatment process that speeds up the natural water cycle to provide a sustainable source of drinking water. The technology is common elsewhere in the world, including the United States of America and Singapore.
• Water recycling plants use advanced techniques to produce highly-purified source water. Special membranes are used to remove salts and a range of other impurities. The process includes reverse osmosis, where water is forced through tiny membranes 50,000 times smaller than the width of a human hair, to remove dissolved salts and impurities, such as bacteria, hormones from pharmaceuticals, and PFAS, so called ‘forever chemicals’. In fact, so much is removed from the water that some essential minerals like calcium and magnesium have to be added back in to achieve the water quality customers are used to.
• If the Hampshire Water Transfer and Water Recycling Project is approved, it would be the first UK scheme to use a Full Advanced Treatment process – including micro-filtration, reverse osmosis, and UV Advanced Oxidation Process. More details can be found online at: https://www.southernwater.co.uk/our-story/our-plans/water-recycling-hub.
• Southern Water is currently carrying out detailed studies and investigations as it explores this option further, including an Environmental Impact Assessment and Habitat Regulations Assessment to consider the impacts of recycled water on the reservoir.
• The first stages of this developing information are being shared with our customers and stakeholders, including via the 29 May to 23 July 2024 public consultation on the Hampshire Water Transfer and Water Recycling Project.
• We are liaising closely with Southern Water as the development of the water recycling proposals move forward, to ensure we fully understand the relevant detail and can continue to work together in the interest of securing future water supplies, while protecting and supporting the environment.

Recreation

• Havant Thicket Reservoir will create a new green leisure hub to benefit both people and wildlife.
• This will include a visitor centre, with a café and other facilities, a new 5km network of paths for walkers, joggers, cyclists and horse-riders, as well as a play area and picnic areas. We’re also considering a number of other leisure activities, including small-scale angling and model boat sailing.
• The commitments we made around recreation for the approved reservoir scheme will be honoured, should the water recycling scheme be approved and delivered.
• Furthermore, we do not anticipate that water recycling would have any negative impact on leisure activities at the reservoir.
• For example, although further analysis and assessments are required, initial studies suggest the recycled water that would supplement the reservoir would, in most respects, be cleaner than the spring water that would be used to fill the reservoir.

We don’t expect there to be any adverse impact on the environment in the local area, if the water recycling scheme was to go ahead.  

We will ensure that all the environmental and recreational commitments made in the original plans for Havant Thicket Reservoir, which received formal planning permission in 2021, are maintained if the Hampshire Water Transfer and Water Recycling Project proposals were to go ahead. This includes delivering an overall environmental ‘net gain’ through the original reservoir scheme.

Southern Water is currently carrying out detailed studies and investigations as it explores this option further, including the impact on nitrate levels in Langstone Harbour. These form part of an Environmental Impact Assessment, with a Preliminary Environmental Information Report being published as part of Southern Water’s public consultation during 29 May to 23 July 2024 on its water recycling scheme proposals.

Although further analysis and assessments are required, initial studies suggest that the highly-treated recycled water entering the reservoir would be cleaner, in most respects, than the spring water that would be used to fill the reservoir. This includes the recycled water having lower nitrate levels than the spring water. We also know that the retention of water in the reservoir reduces nitrate levels over time.

• Water recycling is a well-established and widely-used water treatment process that speeds up the natural water cycle to provide a sustainable source of drinking water. The technology is common elsewhere in the world, including the United States of America and Singapore.