What’s really in your tap water?

Written by William Fryer - MA Oxon

There are many substances in your water in addition to H2O. The majority of these chemicals are there to keep the water safe for human consumption. Chemicals such chlorine are added by water companies to kill off bacteria. Additionally other chemicals may have infiltrated your water supply through leaks.

These chemicals may include PAH (polynuclear aromatic hydrocarbons), lead, copper and zinc depending on the type of pipes installed in your home.

Water distillers and distilled water

Among other trace chemicals in water, most water contains trace amounts of calcium and magnesium. High levels of these will make your water ‘hard’. Hard water can make the water taste odd to those who are not accustomed to it. It also causes limescale in kettles and irons. One study of a primary school in Nottingham also found evidence that calcium deposits found in tap water could irritate sensitive skin and trigger eczema.

You might be tempted to try bottled water, but all bottled water in plastic bottles contains microplastics. 

Rather than spending large amounts of money on bottled water – which is more expensive than petrol – a water distiller will provide pure water, superior to any other method of filtration or purification. And by filtering these chemicals out before you drink water, your body does not need to filter them.

While the UK does have some of the cleanest tap water in Europe, unfortunately there are still many additives and impurities in our water which may be causing your body long term damage. There are up to 79 different polluting chemicals which find their way into our water and could be making you ill. Here are just a few of the major contaminants in tap water and the negative impacts they can have on your health:


Lead gets into our water as it travels through lead water pipes which over time corrode, allowing the lead to enter the water system. Exposure to lead in drinking water can have serious health implications such as kidney problems, high blood pressure and stunted mental and physical growth in children.


Unfortunately, due to leaks in our water systems, biological contaminants can sometimes enter the way supply. When a contaminant such as faeces enters the water supply, it brings with it a host of bacteria and viruses which are likely to make anyone who drinks it very ill. There is also a risk of pathogens entering the water which cause viral diseases such as hepatitis A and norovirus. 


When metal ions such as calcium, sodium and magnesium are present in your drinking water supply, it can result in too many of these metal ions building up in your body, which can lead to hardening of the arteries and also contributes to kidney stones. Water hardness can also cause skin irritations, acne and wrinkles.


When arable farms use fertilises such as ammonium nitrate, these fertilisers can be washed into our rivers when it rains, meaning the nitrates end up contaminating our drinking water. When they get into our body, these nitrates can interfere with your blood’s ability to transport oxygen which can be fatal for children.


Fluoride is added to some drinking water with the intention of improving the health of our teeth, yet there is little evidence to suggest it actually does that. In some cases, it even causes a condition called fluorosis which discolours and damages the teeth. Furthermore, fluoride has been associated with lowering IQ, arthritis, bone cancer and reproductive problems. Flouride is difficult to remove, but water distillers remove all fluoride.


Chlorine (and chloramines) are added to drinking water to kill bacteria, however it can have a damaging effect to the human body too and has been linked to cancer and genetic damage. While water companies argue that chlorine evaporates from the water within half an hour, it is unlikely that you will leave your water for half an hour for this to happen!


‘Pesticides’ is the term covering a wide range of substances such as weed killers, insecticides, fungicides and other similar chemicals. Whilst DEFRA work hard to safeguard drinking water supplies, these chemicals can still be detected.

Growth hormones

Growth hormones designed for cows to encourage milk production can sometimes find their way into our water supply through affected waterways and nearby wild fish.

Giardia Cysts

Giardiasis is a gastrointestinal illness caused by Giardia cysts being introduced into the water supply. The cysts are microscopic and are very resilient, causing diarrhoea, abdominal cramps and gas. The only way to eliminate them is through medication however they have been found to reoccur in some individuals.


The core source of asbestos in drinking water comes from the asbestos fibres in cement water mains decaying and the natural dissolution of asbestos-containing minerals, meaning there is quite little we can do to prevent this. Most studies have not found a correlation between asbestos-infected water, although a small number have found a weak positive association between drinking water and specific gastrointestinal cancers.


Small amounts of pharmaceuticals such as antibiotics can be found in drinking water. This can find its way into our water supply by several different routes: some people flush unneeded medication down the toilets and others take the medication which is then passed through their system into the water supply. Studies have shown that while drinking water is treated and cleansed, some traces can still remain in your drinking water and haven’t yet been proved to be harmless. The only way to ensure 99.9% of these impurities are removed is by using a water distiller. Water distillers are a much cheaper source of pure water than bottled or filtered, which can still contain impurities after the filtration process and is more expensive per litre than petrol! By using water distillers, you can be safe in the knowledge that none of these things will be present in your drinking water.