What Are the Limits for Pollutants in Bottled Water?

Sep 27 2022

With up to 80% of our bodies made from water, it’s a precious resource upon which we all depend for survival. Humans cannot live without drinking water for more than a couple of days, so ensuring everyone has access to clean water that is safe to drink is a basic right. Water which comes out of the tap in the UK is subjected to rigorous testing protocols on a regular basis to keep it free from pollution.

Most people would expect that bottled water would be held to even higher standards; after all, buying bottles of water from a supermarket can be up to 2,000 times more expensive than drinking it at source. But what actually are the limits on pollutants in bottled water in Great Britain? Is it as safe to drink as we assume? We take a deeper dive into the subject below.

By the numbers

The British government requires that all producers of bottled water test their water on a regular basis and ensure it complies with legal limits for chemical, microbiological, pesticides and radioactive substances. Here are those categories and the limits on the pollutants found within them broken down in greater detail:

Chemical limits

Acrylamide	0.10 micrograms per litre
Antimony	5 micrograms per litre
Arsenic	10 micrograms per litre
Benzene	1 micrograms per litre
Benzo(a)pyrene	0.01 micrograms per litre
Boron	1 milligrams per litre
Bromate	10 micrograms per litre
Cadmium	5 micrograms per litre
Chromium	50 micrograms per litre
Copper	2 milligrams per litre
Cyanide	50 micrograms per litre
1,2 dichloroethane	3 micrograms per litre
Epichlorohydrin	0.10 micrograms per litre
Fluoride	1.5 milligrams per litre
Lead	10 micrograms per litre
Mercury	1 micrograms per litre
Nickel	20 micrograms per litre
Nitrate	50 milligrams per litre
Nitrite	0.5 milligrams per litre
Polycyclic aromatic hydrocarbons	0.1 micrograms per litre
Selenium	10 micrograms per litre
Tetrachloroethane and trichloroethane	10 micrograms per litre
Trichloromethanes	100 micrograms per litre
Vinyl chloride	0.50 micrograms per litre

Microbiological bacteria limits

Escherichia coli	0 per 250 ml
Enterococci	0 per 250 ml
Pseudomonas aeruginosa	0 per 250 ml
Faecal streptococci	0 per 250 ml
Sporulated sulphite-reducing anaerobes	0 per 250 ml
Total viable colony count (TVC) after 72 hours at 22°C	100 per ml
TVC after 24 hours at 37°C	20 per ml

Pesticide limits

Aldrin	0.030 micrograms per litre
Dieldrin	0.030 micrograms per litre
Heptachlor	0.030 micrograms per litre
Heptachlor epoxide	0.030 micrograms per litre
Other individual pesticides	0.10 micrograms per litre
Total pesticides	0.50 micrograms per litre

Radioactive limits

Radon	100 becquerels per litre
Tritium	100 becquerels per litre
Indicative dose	0.10 millisievert per litre

Forever chemicals

Although the above contaminants are fairly tightly controlled in both tap and bottled water, there has been mounting concern over levels of so-called “forever chemicals”. Formally known as per- and polyfluoroalkyl substances (PFAS), this group of thousands of chemicals do not degrade in the atmosphere or in the human body, thus potentially accumulating to dangerous concentrations over time.

At present, UK law requires that water companies must only take steps to reduce the amount of PFAS in their product when it exceeds 100 nanograms per litre. Healthcare professionals must be consulted if the levels exceed 10 nanograms per litre, but even this is far higher than the European threshold of 2.2 nanograms per litre, fuelling fears that the UK is falling behind its continental peers with regard to drinking water safety.