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
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.
Chlorination
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
.
