Industry insights

What Is The Treatment Process For Drinking Water In The UK?

2 min read

By Matt Stimpson |  Published

The UK’s drinking water is among the highest-rated in the world, going through stringent treatment and purification process before it reaches our taps. While probably something none of us gives too much thought to, what exactly is involved in the water treatment process and how does it all work?

How the water treatment process works

The water coming from our taps at home is derived from a mix of natural sources: surface water which comes from rivers, reservoirs, and lakes, and groundwater which is from collections of underground reservoirs (also known as aquifers).

Depending on where you live, local water utility companies will generally use a variable mix of both sources to supply their customers but will be limited to what they’re allowed to use for environmental reasons. But whether from a river or an underground source, water goes on a journey to be processed, purified, and treated long before it reaches your home or business.

Water collection and storage

Water pumped and collected from surface or groundwater locations are stored in reservoirs (which also collect rainwater) before the treatment process begins. This provides a good store of water in case of any water shortages. But water stored here also starts a natural cleaning process as heavier, larger particles naturally sink.

Water screening

Once a mix of stored surface and groundwater has been collected and introduced to the treatment plant, it goes through a screening process to remove any natural debris, like branches, twigs, leaves, or even fish, that could cause blockages.

Removing particles

After the screening, chemicals are added to the water that causes dirt and sediment particles to attract each other making small clumps. These form a layer on top of the clean water that’s easier to remove during the treatment process.

Filtration processes

The water then goes through essential filtration processes by going through a rapid gravity sand filter, containing a mixture of gravel and coarse sand. As the water goes through, larger particles are trapped. A second filtration process follows as the water goes through a fine sand or carbon filter to remove any harmful pesticides or contaminants that might be left.

The final treatment

The final stage of the treatment process involves adding a low dose of chlorine to the water to ensure any remaining bacteria are killed off. Once this s complete, the pure, clean water is pumped out to reach every household in the area as 100% safe to drink tap water.

Ongoing testing

This treatment process is largely the same for every water company across the UK. But though it’s a continuous exercise, many thousands of tests and monitoring processes are carried out over the year to test the water’s safety. Find out more about this process here.

Pure-filtered water from Thirsty Work

While your water is completely safe after its treatment, some people can still recognise a certain taste in tap water and prefer filtered water that can help to remove any lingering odours or tastes. And a Thirsty Work mains fed water cooler can do exactly that by using its built-in, advanced filtration system to give you 100% filtered, great-tasting water.

For more information on our mains fed water coolers call our customer service team today on 01392 877 172 or email us at and you can start your free, no-risk 10-day, free trial to taste the difference.