It’s a fair question. After all, we seem to be surrounded it and it regularly just falls out of the sky, so why does the water that comes out of our taps cost money?

Put simply, it’s not just the water you’re paying for, it’s the processes involved in making the water safe and transporting it to and from your business. Any business with a water butt will know that the water collected from rainfall can legally only be used for a limited amount of applications – and that’s a good thing. For human consumption, water needs to go through several intensive filtration steps, and rigorous checks are continually performed to maintain the highest standards.

So, let’s start at the beginning and see where your money goes.

The water that finds our way into our pipes starts off as precipitation. Some of that precipitation ends up in rivers, lakes or in underground aquafers.

Your location in the UK will determine the source of your water and what percentage is from ground water or surface water. About 30% of the water used in England is from aquifers,  and that percentage increases the further south and east you go. Further north and in Scotland, most of the water comes from river and lakes.

Water collected from underground sources requires more intensive processes and infrastructure than water collected from surface sources. After collection, the water enters a treatment process to make it safe to consume.


Mainly used for surface water, screening removes floating objects and debris through the use of grills, screens and filters. Although also screened, water from underground sources often gets naturally screened as it passes through underground rocks.


In the clarification step, a chemical is introduced to the water that causes small floating sediment, like silt and mud, to clump together to make its removal easier.


Filtration sees suspended material in the water gradually sieved out, using a variety of methods including sand filters and screen filters.

flowing pipe


Aeration is the process of injecting air into the water. This allows for oxygen to saturate the water and lessen the amount of dissolved gasses within the water. The temperature of the water is key to the effectiveness of this process, with colder water being most suitable.

Granular Activated Carbon (GAC)

Granular Activated Carbon is a complex chemical system where water is placed into vessels where highly porous carbon molecules absorb unwanted chemicals such as fertilisers, pesticides, herbicides, etc. These GAC molecules are also able to remove organic particles, thus further increasing the water’s quality.

Ozone dosing

In this vital step, ozone is introduced as a potent biocide that disinfects the water by destroying any pathogens and harmful bacteria.

Chlorine and ammonia disinfection

Small amounts of chlorine are added to ensure that harmful microbes are destroyed. Ammonia is also introduced to the water to combine with the chlorine to create a long-lasting disinfectant.


The completely treated water is then tested, with 99.96% of water samples in England and Wales meet the Drinking Water Inspectorate’s standards. This water, now completely safe for human consumption, is then channelled through a vast network of 343,865km of pipes to all our homes and businesses.

But that is only half the story! On the other end, you have the processes and infrastructure that are involved in collecting and treating the wastewater that leaves our homes and businesses and ends up in the 567,256km of UK sewer pipes.  Find out more in part 2 – Beyond the flush.