What's REALLY in your tap water? With millions more Britons about to get ... trends now

What's REALLY in your tap water? With millions more Britons about to get ... trends now
What's REALLY in your tap water? With millions more Britons about to get ... trends now

What's REALLY in your tap water? With millions more Britons about to get ... trends now

Earlier this month it was announced that fluoride will be added to the water supplies of millions more Britons under Government plans to improve dental health.

While the mineral has been added to water supplies in parts of the UK for decades – and NHS and experts including chief medical officer Sir Chris Whitty insist it is inherently safe - the plans are not without controversy and have attracted unfounded internet conspiracy theories.

So what's the truth about fluoride's health benefits and drawbacks? And what else is lurking in our tap water in the UK? Could it be doing any harm?

Our interactive graphic below shows the key chemicals and even pathogens we might unknowingly drink every day.

The specific level of substances detected varied across the country and represent only minute traces per litre. Of the thousands of tests conducted only a small fraction returned a positive result above threshold levels.


Fluoride is abundantly safe at the levels most consume. Yet it's still a huge source of controversy.

Adding it to drinking water is a flashpoint issue in the US, with presidential hopeful Robert F. Kennedy Jr even labelling it 'neurotoxic' and vowing to remove it from drinking supplies if elected.

Britain isn't immune to these sentiments. Both the Green Party and Tories have opposed it in the past, partly in response to pressure from local communities.

Some studies have previously linked fluoridation to cases of Down's syndrome in babies, and rates of kidney stones and even some cancers.

However, the NHS and experts like Sir Chris Whitty say these claims are 'exaggerated and unevidenced'.

Outlandish conspiracy theories touting fluoride as a plot by the global elite to depopulate the world or that it is being used for mind control purposes are also frequently spread online.

Only one health issue has been definitely linked to fluoride: a problem called fluorosis. Dental fluorosis is the most common form and occurs when a child's teeth are exposed to too much of the mineral while developing.

This leads to fine, pearly white lines or flecking appearing on the surface of the teeth.

Severe cases can cause the tooth's enamel to become pitted or discoloured, however health officials say this is incredibly rare in the UK.

A more extreme version is skeletal fluorosis, but this typically occurs in areas where fluoride levels are naturally high, rather than places where it is artificially added.

The risk of fluorosis is one of the reasons why the World Health Organization (WHO) recommends fluoride in drinking supply shouldn't go above 1.5 mg/L, a limit also set in the UK.

In the UK, excess fluoride of any source is removed in drinking water as part of the treatment process to bring it to at most the standard 1.5mg/L level.

Some 6.1million people in England, about one in 10, currently receive fluoridated water.

More than six million people in England, about one in 10, currently receive fluoridated water.

More than six million people in England, about one in 10, currently receive fluoridated water.

However, this is set to change with the Government vowing to add fluoride into the supplies of another 1.6million people, with further expansions planned for the future.

Latest data from the Government's Drinking Water Inspectorate (DWI), which monitors drinking water supplies to ensure they meet safety parameters, shows there were zero fluoride breaches for public water supplies in 2022.

Public water is what the vast majority of the population in England receive because it is supplied by water companies.

However, 1.4 per cent of tests for private water supplies, those provided on site in rural areas, such as farms, as well as some hotels and resorts, breached UK fluoride restrictions.

The safety of private water supplies is the responsibility of the area's relevant local authority.

Professor Alan Boobis, a toxicology expert at Imperial College London and government advisor, said levels of fluoride in water in the UK are not a health concern.

'I do not believe that there are any specific health concerns from exposure to fluoride at the safety standard levels,' he said.

However, he added that he didn't believe universal fluoridation of water supplies in Britain is needed to prevent dental problems as background levels are high enough to achieve sufficient benefit.

Professor James Caulson, a toxicology expert at Cardiff University, agreed that levels of fluoride in water are of little cause for concern.

'Patients exposed to doses of less than 5mg/kg body weight are unlikely to show features of toxicity (350 mg for an adult).

'Daily doses of 20 to 80 mg over 10 to 20 years are associated with chronic fluorosis (staining of the teeth).

'The upper limit of 1.5 mg/L (equivalent to 0.06 mg/kg for a 70 kg adult drinking three litres a day) is likely to be protective.'

However, he added that when considering these figures, drinking water is not the only source of many substances and people can consume more through their diet for example.

Professor Caulson added that specific figures can change for children and those with health conditions.


The main risk from lead in drinking water comes from the historical use of the metal in pipes before the dangers were realised in the 1970s.

Lead poisoning is a concern both in the immediate and the long term, especially for children.

The heavy metal is known to adversely impact mental development effecting their IQ later in life and is also suspected of increasing behavioural problems.

Lead poisoning can also lead to heart and kidney disease as well as contribute to high blood pressure in adults.

As such the DWI's limit for safe lead exposure in UK drinking water is just 10 micrograms per litre (μg/L).

This level was found to have been breached 59 times across England in 2022, the majority (17) from Thames Water.

Professor Boobis said: 'Exceedance of the safety standard for lead would only be of concern if this continued for some time, as lead builds up in the body over years, before it reaches levels adverse to health.

'Of course, if the exceedance was substantial this would be of concern even short-term.'


Dubbed 'forever chemicals' for their ability to persist in the environment for years, these are a family of man-made compounds famed for their durability and stain resistant properties.

They have been used in a host of products from nonstick cookware, to clothes, packaging, cosmetics and even children's toys.

But studies have since linked the chemicals to a variety of cancers, blood disorders, fertility problems and birth defects.

While these links are not definitive and research is ongoing, part of the concern is because PFAS are so ubiquitous in modern life and persist so long in the environment they could infiltrate water supplies, further increasing exposure.

The DWI currently sets a limit of 0.1μg/L for PFAS in UK tap water, with the body running a specific programme testing for levels in British water supplies.

It states: 'The DWI is working closely with the UK Health Security Agency, the Environment Agency and Government, to adopt the most up to date information regarding standards and toxicology.'

It continues: 'We are also carrying out our own research on analytical methods, and risk assessment to inform our decision making.'

Professor Boobis said unlike many of the other substances measured in British drinking supplies, research about the health impact of PFAS, and by extension the safe limit to consume, is ongoing, making it hard to calculate safe exposure limits.

That being said, he added: 'PFAS take some time, years, to accumulate to maximum levels in the body.

'Hence, the duration over which levels exceed the safety standards is important.

'Personally, I do not worry about PFAS in my drinking water, but I can well understand that others will be concerned'.


Pesticides, chemicals made to kill unwanted weeds and vermin, can enter British water supplies via runoff from gardens and farms as well as other sources.

Given they are designed to kill and harm - unlike many of the substances listed - it's unsurprising limits of pesticide content in water are strict.

The DWI sets a limit of 0.5μg/L for the total of amount of all pesticides in tap water, but this is set to 0.1μg/L for some specific types.

This latter limit was breached three times in 2022, all by water supplied by Northumbrian, Essex and Suffolk Water Ltd.

They related to the herbicides metazachlor and propyzamide, both chemicals commonly used in the farming of rapeseed.

While levels in water may sound concerning, Professor Boobis said the standard set is very safe with the DWI looking at a detection rate, where a substance can be spotted, not the safety limit for human exposure.

'The safe levels based on health effects are both more than four orders of magnitude greater than the safety standard levels in water,' he said.

'Hence, there is no basis for concern over traces of these pesticides in water.'


Bacteria normally found in our guts can sometimes be found in tap water.

Both types measured by regulators (E.coli and Enterococci) can, in theory, make people ill, though for most people this is usually mild.

Instead their presence is normally measured as an indicator that water supplies may have been contaminated by human faecal matter.

As such the DWI sets the limit as 0 bacterium per 100ml, meaning that, at least in principle, no such bacteria should ever be detected in home supplies.

This isn't the case though, with 27 breaches detected in 2022. The vast majority (12) were from Severn Trent Water, which supplies 4.5million homes and businesses in the Midlands.

And at least 5,577 Brits on private supplies drank water contaminated with faecal matter in 2022.

Professor Paul Hunter, a renowned infectious diseases expert from the University of East Anglia and who has advised the WHO on standards for drinking water, said these pathogens are unlikely to make a Briton ill but are good indicators of contamination.

'They are generally not hazardous in themselves but are an indication that the water could have been contaminated by faecal matter,' he said.

'There are

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