We take it for granted that our supply of drinking water is available from every tap in our homes. But how does the water actually get there? In this post, we’ll look at the journey water makes to eventually make its way into our taps. We’ll also look at the process it goes through to ensure that it is safe for us to drink.

The luxury of supply

In developed countries, an average of 1000 litres of water is used per person each day. We use it to drink, cook, wash and flush the toilet. In undeveloped countries where the water is not piped into homes, the average person uses just 5 litres per day. Dr Heather Cruickshank at Cambridge University writes:

“Many people who lack access to safe water live in regions where conventional methods for supplying drinking water through water pipes are simply not possible or cost-effective. For these people, the alternative is to use household water treatment and safe storage systems (HWTS) based on chlorination, solar disinfection, ceramic filters or biosand filters.”

Incredible journey

In the UK we are fortunate to have the luxury of water running directly into our home. But how does it get there?

It all begins at the reservoir, river or lake. The collected water is transported to a treatment plant through pipes. When the water is at the treatment works, it goes through several processes, the first of which is filtration. Solid debris in the water like leaves and soil must be removed. This is done by spraying water onto a filter bed, made from specially prepared layers of gravel and sand. Large pieces of material are filtered from the water in the upper strata, and smaller pieces by the strata below.

After this, the water moves into a sedimentation tank, aluminium sulphate is then added to clump particulate matter together, larger particles being easier to remove. The water is then pumped through a fine filter which takes care of the other tiny particles.

The water is then chlorinated: this is done to ensure that there are no microbes present in the water. Adding chlorine to the water sterilises it. Diseases such as cholera, typhoid and dysentery might be present in untreated water, and can be fatal.

In some areas of the UK, fluoride is added to the water supply. Fluoride can improve dental health by reducing tooth decay. After the treatments, the water is then pumped along a network of pipes and into your home.

Fluoride debate

Around 10% of the UK population receive a fluoridated water supply. In some areas, the water is naturally fluoridated with calcium fluoride. There are currently five UK water companies that fluoridate the water supply. The Water Act, 2003 required water companies to comply with the requirements from local health authorities to fluoridate their water. There has been some controversy over the adding of fluoride to water supplies. Some people argue that fluoride does not improve dental health. It is also claimed that fluoride is linked to tooth staining, bone disease and pain. There is also an argument that the addition is unethical, since it forces people to consume fluoride whether they agree with the policy or not.