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Southern Water worker conducting water tests

Water recycling

Water recycling is a tried and tested technique that will provide a reliable water supply to customers even in times of severe drought. Water recycling will reduce the amount of water we need to take from the environment.

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Why do we need water recycling?

The south of England is water stressed. We rely on our natural environment for the water we need but there isn’t an endless supply.

We’ve already agreed to reductions in the amount of water we can take from rivers during a drought and need to find new sources of water to make up the shortfall. Meanwhile, population growth and climate change are continuing to put pressure on the demand for water and the environment's ability to provide it.

This, combined with the responsibility of us all to protect our environment, means if we do nothing, we’ll face a shortage of water.

To keep taps and rivers flowing, we need to take a fresh look at the water we waste. Water recycling, alongside reducing leakage and improving water efficiency, is an essential next step to ensuring our water supplies are truly sustainable and fit for the future.

What’s the process?

Water recycling speeds up the natural water cycle. It’s a process that’s been used around the world for more than 40 years. 

1

Membrane process

Water already extensively cleaned at a wastewater treatment works is pumped through two filtering processes. This includes pushing water at high pressure through a membrane of tiny holes more than 50,000 times smaller than the width of a human hair.
2

Advanced oxidation process

Reverse osmosis is extremely effective at removing impurities. But as an extra layer of protection ultraviolet light is applied along with a small dose of a chemical called hydrogen peroxide. These are widely used around the world in water recycling.
3

Treated water conditioning

To make the water drinkable, minerals such as calcium and magnesium salts that have been removed during the easiest stages of treatment are added back in. This ensures it meets strict water quality standards.
4

Waste handling

Water and particles removed by each of the previous stages of treatment are taken away to be cleaned. The liquid is filtered to produce cleaned Wastewater known as reject water, which can be released back into the sea.
5

Environmental buffer

The treated water is pumped to a lake reservoir or watercourse known as an environmental buffer where it mixes with existing water from other sources.
6

Water supply works

Water can be taken from the environmental buffer and pumped to a water supply works where it is treated to the same rigorous standards as all water taken from the environment. Typically this involves a combination of filtration methods and the addition of chlorine.
7

Reject water release

As about 20% of the source water is filtered out through the various treatment processes, reject water is released back into the sea. An underwater pipe with a series of holes at the end called a diffuser helps disperse it across a wider area.

Water recycling around the world

Recycled water is a safe source of drinking water which is widely used in other parts of the world including Australia, Singapore, the USA and Sweden. The global water recycling map shows every water recycling project across the world.

Our regulators recognise water recycling is an important part of future water supplies – see what the Drinking Water Inspectorate has to say on the matter.

Frequently asked questions

Check out our frequently asked questions for more information about water recycling and what else we're doing to ensure a reliable water supply.

Yes, water recycling is a safe, established method of water treatment that's already used elsewhere around the world. Water recycling adds further layers of treatment for the already-common practice of pumping highly treated wastewater into rivers, where water is abstracted further downstream for supply. Water recycling produces highly treated, purified water that would be pumped to a Water Supply Works for further treatment in order to meet strict water safety standards.

No – the water recycling proposals are fundamentally different, and separate, from the current system of stormwater releases, which are designed to protect homes from flooding.

Stormwater is wastewater that has been heavily diluted by rain and is sometimes released to the environment to reduce the risk of flooding to homes and businesses.

Recycled water is purified water that has gone through a series of advanced treatment techniques so it can be used as a source for drinking water supplies.

We’re cutting down leakage, improving water efficiency and working with neighbouring water companies to share supplies. These improvements will help save water but we need to find new sources to make sure we can take less from the environment.

Our Target 100 campaign is an industry-leading programme that aims to achieve a reduction in customer consumption from an average of 130 litres per person per day, to 110 litres by 2040 and 100 litres by 2050. We’re doing this by encouraging, supporting and incentivising our customers to understand the value of the water they use.

At the same time, we’re investing in new, innovative ways of finding and fixing leaks to keep water in the network. We’re committed to reducing our leakage rate by 15% by 2025, 40% by 2040 and 50% by 2050.