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Bladder cancer linked to THMs in UK tap water

Bladder cancer linked to chlorine by-products in UK & European drinking water.

Breaking news from scientists confirms what we at PureH2O Ltd have been saying for decades: impurities, pollutants and contaminants in UK tap water are associated with risks to human health – including the development of bladder cancer.

Research by the Barcelona Institute for Global Health (ISGlobal), published this month in Environmental Health Perspectives, estimates that 1 in 20 cases of bladder cancer in the UK can be linked to the presence of trihalomethanes (THMs) in tap water. (Evlampidou, 2020)

Fortunately, PureH2O tap water purifiers remove THMs to protect your health.

What are THMs?

THMs are by-products of the chlorine disinfection process used by most municipal water treatment plants in the UK and Europe. Chlorination has been used since the 1900s and is an effective disinfectant that reduces illness from water-borne pathogens (Do, 2005).

However, there is a growing body of research from Europe and North America that shows that long-term exposure to chlorine by-products THMs is associated with an increased risk of bladder cancer. (Evlampidou, 2020)

We’ve always linked the presence of pollutants such as THMs with degenerative health problems, and this recent study appears to substantiate the claims we’ve been making.

Detail of a partially blurred periodic table of the elements. Focus on chlorine
Chlorine is used to disinfect drinking water; its by-products are associated with bladder cancer

UK suffers one of highest rates of bladder cancer attributable to tap water THMs.

Researchers analysed tap water monitoring data from 26 European countries and found that the UK was one of 9 European countries where maximum THMs concentration recorded exceeded the permitted limits of 100 micrograms per litre of water.

The study estimates that the UK suffers the second highest rates of bladder cancer cases attributable to THMs, at 20.7%.

“Spain (22.6%), the United Kingdom (20.7%), and Romania (16.0%) accounted for the largest estimated number of attributable cases.” (Evlampidou, 2020)

Other European countries were estimated to have much lower rates of bladder cancers attributable to THMs: Ireland 1.7%, Sweden 1.3%, Germany 0.6%, and the Netherlands 0.1%. The European-wide average across all 26 countries was 4.9%.

glass with water flowing from a tap
Researchers recommend changes to water treatment procedures.


Researchers recommend changes to water treatment & distribution.

Although researchers admit that there have not yet been enough large-scale studies to definitively prove a causal relationship between THMs and bladder cancer, they warn:

“our results suggest that current THM exposures in the European Union may lead to a considerable number of bladder cancer cases that could be avoided…” (Evlampidou, 2020).

The study recommends changes to water treatment and distribution protocols. If relevant parties agree to this, how long will that take? And do you want to continue drinking tap water in the meantime?

What can regulators do about this?

Even if regulators were quick to take action to reduce THMs from chlorination, they would have to use other disinfectants, which bring their own health risks. As the authors of the recent ISGlobal study explain:

“Disinfectants are highly reactive by definition, and any one of them will lead to the formation of [disinfection by-products] DBPs (Hua and Reckhow 2007). Most of them are not regulated, and many are considered carcinogenic and/or genotoxic and have been associated with bladder cancer (e.g., nitrosamines) (Richardson et al. 2007).” (Evlampidou, 2020)

In other words, whatever chemicals are used to disinfect tap water, their by-products are associated with bladder cancer.

Further tap water contaminants also associated with various cancers.

THMs are far from being the only thing to worry about in tap water. Nitrates are linked to colorectal cancer and endocrine-disruptors to breast cancer. As our M.D. Roger Wiltshire explains:

“Whatever their concentration, the presence of microplastics, nitrates, fluoride, pesticides (including the slug poison metaldehyde), heavy metals, cocaine and other drug residues, flame retardant (2D4) and countless other compounds can only have one effect on human health, leading to degenerative illness.”

We believe there are no acceptable levels of pollutants, contaminants and impurities in the water you drink.

Comparison of Tap Filtered, Bottled and Pure Water
PureH2O water is purer than all bottled waters.

What can I do to protect my health?

Jug filters may slightly improve the taste of tap water and somewhat delay the build-up of scale in your kettle, but that’s about it. You won’t want to opt for bottled water because of its massive environmental burden and the fact that it may be even more contaminated by certain substances than tap water.

The safe, effective and sustainable way to protect your health is to use a PureH2O Reverse Osmosis tap water purifier. Our technologically advanced purification systems remove chlorination by-products THMs – and more – from tap water for your total peace of mind.

Reverse Osmosis water purification.

It’s not as complicated as it sounds.

PurityPro water purifiers typically fit in the cabinet under your kitchen sink. They work quietly and efficiently, day in day out, to remove up to 99.99% of all contaminants and impurities found in UK tap water, including THMs.

The water is fresh, pure and means we don’t have to buy bottled water.” – Paul.

under sink water purifier
PureH2O PurityPro tap water purifier with optional Quatreau Touch tap.

You can get a PureH2O tap water purifier fitted in your home or workplace quickly, easily, and cost-effectively.

I’ve had a system from PureH2O Ltd for 18 years and I can only praise the PureH2O team for their ability to maintain the quality of water it produces with just one annual service visit. The taste is just brilliant.

How to order your tap water purifier.

Protect your health and order your PurityPro tap water purifier today. Call us on 01483 617000 fill in our contact form or email

We offer purchase outright, rental options or 0% finance with repayments spread over 12 months. Our team of specially trained engineers install your system and service it annually to ensure it continues to protect your health for years to come – and our extended 10-year Parts & Labour Cover (subject to Service Agreement) offers total peace of mind!


Iro Evlampidou et al Trihalomethanes in Drinking Water and Bladder Cancer Burden in the European Union Environmental Health Perspectives, Vol. 128 No. 1. 15.01.20 accessed 22.01.20

Minh T. Do et al Chlorine Disinfection By-Products and Pancreatic Cancer Risk Environmental Health Perspectives, Vol. 113 No. 4 10.01.05 accessed 23.01.20

S E Hrudey et al Evaluating Evidence for Association of Human Bladder Cancer with Drinking-Water Chlorination Disinfection By-Products Journal of Toxicology and Environmental Health Vol. 18 No. 5 04.07.15 accessed 23.01.20

Further Reading

Nitrates in Drinking Water Increase the Risk of Colorectal Cancer

Endocrine-disruptors in tap water linked to breast cancer


Helpful Links

About Bladder Cancer – Cancer Research UK

Action Bladder Cancer UK

Fight Bladder Cancer – a UK charity

May is Bladder Cancer Awareness Month


PureH2O Ltd manufactures, installs and maintains the world’s most innovative water purification systems and the most technologically advanced boiling, chilled and sparkling water taps. Since 1991 we have been committed to providing our domestic and commercial customers with the purest, safest, most sustainable choice of drinking water, which helps them reduce their environmental impact by avoiding single-use plastic bottled water.

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