A clear, public‑friendly explainer based on the 12 most commonly asked questions.
Q1. What exactly is “effluent recycling”?
Effluent recycling takes the final treated sewage effluent from a sewage works (e.g. Budds Farm in Havant), puts it through extra high‑tech treatment (including Reverse Osmosis), and then pumps it into a reservoir or river. From there, it is abstracted again and treated as drinking water. This would be the first time in the UK this treatment system is used for public water supply.
- To find out more click here (Link to text in A below)
Q2. Will this recycled effluent come out of my tap?
Yes. If you live in mid or south Hampshire, West Sussex or the Isle of Wight, you will receive recycled effluent in your drinking water – whether you are a Portsmouth Water or Southern Water customer.
Q3. How much will this cost?
A lot. For the Hampshire effluent recycling scheme;
- More than £1.7 billion to build, with costs spiralling
- More than £13 million a year to run
- Plus decades of debt repayments
All of this is paid for by Southern Water customers. And unlike a new reservoir, the project leaves no long‑term legacy once decommissioned.
Q4. Will Havant Thicket Reservoir be affected?
Yes — significantly. The pollution risk is increased, and not all contaminants are removed by the recycling process. Everyday small amounts of pollutants will be discharged into the reservoir including.
- Pharmaceuticals
- Pesticides
- PFAS “forever chemicals
It destroys the opportunity to create the world’s first chalk‑spring‑fed reservoir, a unique biodiversity opportunity lost.
- To find out more click here (Link to FAQ7)
Q5. What happens to the waste from the recycling plant?
The plant produces a reject stream that is four times more concentrated than today’s Budds Farm effluent. This, plus treatment chemicals, cleaning agents and by‑products, will be discharged into the Solent.
Q6. Are the regulations strong enough?
No. Current UK regulations do not provide the level of oversight used in other countries. There is no provision for independent, routine auditing of the effluent recycling plants, nor the sewer system — and none is planned.
The Environment Agency have confirmed they can not set limits on discharges into the reservoir or the Solent for all of the contaminants of concern.
Q7. Can Southern Water be trusted to run this treatment safely?
Southern Water has a long record of:
- Pollution incidents
- Over £90 million in fines
- £126 million in penalties for manipulating regulatory data
This raises serious questions about whether they can safely operate a system this complex, which is new to the UK for public water supply.
Q8. Why build the recycling plant on a contaminated landfill site?
The proposed Broadmarsh site is a historic landfill. Construction risks disturbing contaminants and increasing leachate entering Langstone Harbour.
- To understand concerns about the location of the effluent recycling plant, click here
- To view the location of the landfill site, ‘Site 72’, click here
Q9. Is this a climate‑friendly solution?
No. Effluent recycling requires huge amounts of energy to treat the water and pump it over 40 km to Otterbourne. This creates very high carbon emissions and is not considered a sustainable option.
Q10. Why not fix leaks instead?
In 2024/25, 19% of all water Southern Water took from the environment was lost through leaks. Even by 2050, after spending billions on effluent recycling, 10% of this expensive manufactured water will still be leaking from the system.
Q11. Is “water recycling” different from “effluent recycling”?
No. Southern Water has simply rebranded the term. The process – and the risks – are the same.
Q12. Are there better alternatives?
Yes, more sustainable, lower‑impact options exist, which could be cheaper. These should be prioritised and developed before resorting to effluent recycling.
If you want to find out more about the community’s concerns click here.
Who will get the recycled effluent at their taps?
If you live in mid/ south Hampshire, West Sussex or the Isle of Wight recycled effluent is coming to your taps.
- If you are a Portsmouth Water customer in Hampshire or West Sussex you will receive it via the Havant Thicket Reservoir. Whenever the reservoir is drawn down in a drought or due to an operational emergency you will receive a mixture of spring water and recycled water from the Southern Water effluent recycling plant. After 2040 you will receive the mixed reservoir water more routinely.
- Southern Water have confirmed that most of their customers in Hampshire will receive the recycled water, with mixed water being transferred daily from the reservoir to their Otterbourne Water Treatment Works, which serves mid to south Hampshire including Southampton & Winchester.
Larger volumes of recycled effluent will be pumped into the reservoir in a drought and transferred to both Southern Water & Portsmouth Water drinking water treatment works.
- If the effluent recycling scheme goes ahead Southern Water also plan to build a new pipeline to carry the mixed water from the reservoir to their treatment works near Pulborough, suppling a larger area of West Sussex from Midhurst across to Horsham.
- Southern Water also plan to build effluent recycling plants at Sandown to supply the IOW and near Arundle/ Littlehampton to supply more of West Sussex.
What treatment processes will be used to recycle the final effluent from Budds Farm WWTW?
What do we know about the Budds Farm WWTW where the final effluent will come from?
- The Budds Farm Wastewater treatment works (WWTW) receives raw sewage from a wide area including Portsmouth, Cosham, Havant, Waterlooville, Horndean & Hayling Island.
- Southern Water advised that about 16% of the raw sewage arriving at Budds Farm WWTW comes from commercial sources. This will include industrial sources such as hospitals, silver & nickel plating, engineering works etc.
- The works also receives tankered waste from other sewage works.
- Southern Water have no plans to identify & improve the management of risks in the sewage catchment, before effluent recycling commences, despite this being identified as good practice in other drought-stricken countries that use water recycling.
- Budds Farm experiences saline intrusion into pipework due to its location on the coast. The treatment process will not remove all of the salt before the recycled effluent is discharged into the reservoir.
- It is the final treated effluent from Budds Farm that will be pumped over to the proposed effluent recycling plant at Broadmarsh. This is the effluent that would have been discharged to the Solent via the long sea outfall.
- Research based on data obtained from Southern Water shows the effectiveness of the treatment process at Budds Farm WWTW can be very variable, especially during high volume storm events. Treatment is up to 80% efficient during dry weather but can drop down to 46% during storm events.
- Water quality at Budds Farm is expected to deteriorate with time (statement taken from a Southern Water report).
- A Southern Water treatment specialist advised that the effluent recycling treatment process needs a fairly consistent water quality stream for the effluent recycling treatment process to be most effective. But can the works deliver that?
- Even with robust treatment not all of the contaminants are removed, it depends on the contaminant.