Each glass of tap water contains 10mn 'good bacteria' from water pipes – study

© Eric Thayer
When you drink a glass of tap water, you're ingesting around 10 million bacteria found in water pipes and purification plants. But don't worry – while it may seem utterly disgusting, the bacteria are actually good for you, according to a new study.

Researchers from Lund University in Sweden have discovered that bacteria and other microbes are found in the form of a thin, sticky coating in drinking water treatment plants and on the inside of water pipes.

Known as a 'biofilm,' the coating is inescapable because every surface involved in the process of getting drinking water to your tap is covered in it.

But according to the researchers, there's absolutely no need to worry. In fact, you should be happy – because they suspect a large part of water purification happens inside the pipes, and not only in purification plants.

"We suspect there are 'good' bacteria that help purify the water and keep it safe – similar to what happens in our bodies. Our intestines are full of bacteria, and most of the time when we are healthy, they help us digest our food and fight illness,” researcher Catherine Paul said.

Although the biofilm is seen throughout the process, spotting it hasn't always been easy.

"A previously completely unknown ecosystem has revealed itself to us. Formerly, you could hardly see any bacteria at all and now, thanks to techniques such as massive DNA sequencing and flow cytometry, we suddenly see 80,000 bacteria per milliliter in drinking water," Paul said.

Paul and her colleagues noted that there is great variety among the bacteria and microbes, with at least a couple of thousand different species living in water pipes.

Although the research was conducted in southern Sweden, the researchers stressed that bacteria and biofilms are found all over the world in plumbing, taps and water pipes.

The scientists believe the study will be useful for countries when updating and improving their water pipe systems.

"The hope is that we eventually may be able to control the composition and quality of water in the water supply to steer the growth of 'good' bacteria that can help purify the water even more efficiently than today," Paul said.