An Overview of Tap Water in London

The city of London has been a leading capital for hundreds of years.

It’s famed for a lot – food, architecture, culture –  but is its water considered top of the line?

While those in the United Kingdom are considered to have some of the best tap water in the world, it doesn’t mean that everything is perfect. Let’s take a look at its largest city.

Where does the water come from?

London is mainly supplied by water from the River Thames, the largest river in England. While seventy percent comes from reservoirs from the west of the city, the other thirty percent comes from groundwater, mostly a result of rain that has seeped into the soil. There are many large reservoirs in the metro area that store water until it’s ready to be treated.

Once at a municipal plant for treatment, the water goes through a process that purifies that water in question: filtration, disinfection and supplementary treatment, which in some countries includes the fluoridation of water. Per day, the river provides about a million liters into London’s water supply, even more so during hot days when demand is high.

After the treatment plant, the treated water is sent to the main pipe line that surrounds London, where it ultimately makes its way to the taps of about nine million residents. Once it arrives, the first aspect that residents may notice is the “hardness” of London water.

Why is the water in London hard, but not in other places?

Water hardness is known as the total amount of dissolved calcium and magnesium in the supply. This may lead to dry skin and scale forming, among other annoyances.

The reason? The west of London has chalk and limestone geology.

While hard water has not been noted to negatively impact the health or the development of humans, there have been concerns about contaminants and other unsavories in the city water, such as the alarming presence of sex hormones. In London specifically, the main focus is on the oestrogen hormone, which is found in the contraceptive pill and finds its way into the water supply through excretion.

As a result, this has been referred to as a “fertility timebomb.”

Unwanted Sex Change?

At the start of the last decade, the United Kingdom faced a bill of thirty billion pounds in order to clean up waterways contaminated by synthetic hormones from birth control pills. Research was finding that close to half the male fish in England had changed to female.

And contamination through synthetic hormones isn’t the only problem. In 2017, the largest water company in the United Kingdom, Thames Water, was fined £20m for releasing 1.9 billion liters of raw sewage in the River Thames.

The long-term impact on Londoners, male and female, is yet to be determined.