Where Does Tap Water Come From in the UK? | Virgin Pure

By Bob Fear

Where Does Tap Water Come From in the UK? | Virgin Pure

It’s easy to take drinking water for granted in the UK as it comes straight out of our taps every day, and we expect it to be clean and safe. But have you ever thought ‘where does tap water come from?’ The answer’s not as simple as you might expect. Our tap water has to go on a journey that may be well over a hundred miles from our homes. It also undergoes a treatment process that makes it safe to drink. In this article we explain the whole process that brings you water whenever you turn on your tap.

Where exactly does tap water come from?

The water that comes out of our taps in the UK starts off as rain. That rain either flows into rivers and streams, is collected in reservoirs or is filtered underground. The water companies in England, Wales and Scotland supply over 16.5 billion litres of water a day to a population of over 65 million.

Surface water

Most of the UK’s tap water comes from surface water. This is water from natural rivers and lakes as well as human-made reservoirs. Technically, surface water means any body of water above ground.

There are currently 474 sources of surface water in England and Wales and 339 sources in Scotland. 64% of England’s drinking water comes from surface water, compared to nearly 93% of Wales’ water.


Groundwater is found in the fractures and spaces between geological formations of rocks, sand and soil underground. These formations are called aquifers. Groundwater is stored in aquifers or moves slowly through them, thereby effectively filtering it.

There are currently 2,259 underground sources of tap water in England and Wales and 86 in Scotland. Although there are more underground sources in England and Wales, more of their tap water comes from surface water. 30% of England’s tap water comes from groundwater, compared to only 6% of Wales’ tap water.

Mixed sources

According to the latest report from the Drinking water Inspectorate (DWI), 6% of England’s drinking water (and just under 1% of Wales’) comes from ‘mixed sources’. The DWI does not specify what these sources are.

Some countries recycle their wastewater. These ‘toilet-to-tap’ solutions are seen as a solution to increased water shortages, where climate change adversely affects water treatment plants’ ability to collect, reserve and recycle enough water for a growing population.

Thames Water are planning to implement a wastewater recycling scheme by 2025 , and the UK’s Environment Agency has said toilet water could be pumped into rivers near treatment plants so it can be collected and processed as drinking water by 2030.

However, we are already effectively drinking recycled wastewater as water treatment plants regularly flush diluted wastewater into our rivers when their systems cannot cope with large amounts of rainfall. The Environment Agency itself has said that water companies in England legally dumped raw sewage into rivers over 400,000 times in 2020 as ‘a necessary part of the existing sewerage system’ . In 2022, the Environmental Audit Committee said untreated wastewater was regularly being illegally dumped .

Find out more about why water companies pump sewage into our rivers and seas , here. 

Why does tap water come from different sources?

Water is sourced differently depending on the particular needs of the local area and the water resources available. If demand goes up, the usual source of where water comes from might change to ensure water supply remains constant. Having alternative sources means that water remains available on tap in every home.

How does water get from source to tap?

Knowing where tap water comes from is one thing, but knowing and understanding how it gets from source to tap is another question. Untreated water from rivers, lakes, reservoirs and underground sources is pumped to water treatment plants around the UK. Currently, there are 1297 different water treatment works across England, Wales and Scotland responsible for providing properties with drinking water. As the quality of the water they treat varies according to where they’ve sourced it from, so their types of treatment will vary.

Removing large contaminants from water

Larger water treatment works will store water in reservoirs. This is so they have a larger supply of untreated water available if it doesn’t rain for a long period. While all waterworks will screen collected water to remove items such as branches and leaves, larger, heavier contaminants in untreated water will fall to the bottom of reservoirs, saving the need for treatment plants to manually remove them. Some waterworks use a process called flocculation. This is where a chemical coagulant is added to water which causes small particles to bond together, making them easier to remove.

Water filtration processes

Smaller particles are removed by passing the water through a rapid gravity filter. This is a tank of coarse sand which traps some contaminants. Water is then filtered through large beds of fine sand. These slow sand filters remove even smaller particles. Some treatment works create chemical reactions in water to remove microscopic and dissolved particles, via processes such as ozone, carbon and ion exchange.


The final treatment that drinking water undergoes before it’s pumped to our properties is chlorination. Chlorine is added to the water to disinfect it of organisms and bacteria. This keeps the water safe from reinfection while it’s stored in covered reservoirs before being sent through a network of pipes and pumping stations on its way to our taps.

Read more about the chlorine in our tap water , here. 

Is tap water actually good for you?

Understanding ‘where does tap water come from’ and the processes that go on behind getting your water from source to tap, will allow you to know whether it is safe to drink or not. The UK water authorities, on the whole, provide safe tap water for us all to drink. Drinking plenty of water is essential to maintaining our natural levels of hydration. Around two thirds of our bodies are made up of water, so it makes sense that we should replace all the fluid we naturally lose throughout the day to stay in fit and healthy working order. When we get dehydrated, as well as feeling thirsty, we may start to feel tired, groggy, irritable and we may experience headaches or a reduced ability to concentrate and focus.

Read more about the adverse effects of dehydration .

How much should we drink and where should we drink it from?

The UK government’s Eatwell Guide suggests we drink around six to eight glasses of water a day to maintain our body’s water balance. But some people can be put off by the taste of their tap water. Knowing where your tap water comes from and the filter processing is vital to make a correct decision about how much you should be drinking, and where you should be drinking it from.

Those living near water treatment plants may have more chlorine in their tap water than those who live further away, as chlorine evaporates after a while. The DWI recommends we filter our tap water ourselves to remove the chlorine.

The DWI also suggests we only drink freshly drawn water from the cold water tap directly off the water mains, usually the cold tap in our kitchen. They say not to drink or use the water from our bathroom taps for cooking as it usually comes from a storage tank in the loft so won’t be as fresh as from our kitchen tap. But if you haven’t run any water for several hours, fill a washing up bowl before drinking any tap water. The DWI recommends that we don’t drink water which may have been standing for a long time in our pipes.

If you’re concerned about your tap water, read more about the different contaminants here.

Why is tap water hard in some places?

Depending on where your tap water comes from, some people may find that their water tastes slightly off and contains lots of tiny white flakes. This may be due to hard water. Hard water is when our water supply is drawn from groundwater that’s been filtered through porous underground rocks like chalk and limestone, so there’ll be more minerals floating around in it. While water rich in materials can be healthy, limescale can form when calcium and magnesium bond. As well as affecting the taste of your water, this can cause significant damage to your home appliances.

Read more about hard water and where it is mostly found in the UK

In this article we’ve discussed exactly where tap water comes from in the UK and all the different types of treatment it undergoes by the local water authorities to make it safe for us to drink. Drinking water is essential to our everyday health. If you don’t like the taste or smell of your tap water, and you don’t like the presence of chlorine or limescale, you can always purify your tap water yourself at home. The Virgin Pure Home Water System removes unwanted contaminants from your tap water while leaving in the essential healthy minerals you’d expect to find in bottled water.

Find out about the benefits of a home water purifier .  

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