The full story

For all of us, filtering our drinking water should be a serious consideration, given the weight of evidence of harmful contaminants in the mains supply.

The Royal Society of Chemistry has reported that between 35 and 37 percent of water courses tested in England and Wales contain medium or high-risk levels of PFOS and PFOA respectively. These are common types of PFAS (per- and polyfluoroalkyl substances), dubbed ‘forever chemicals’ because they are virtually indestructible in the natural environment or in our bodies.

Many of these PFAS with which we come into contact in our daily lives carry serious health risks. These include cancer, thyroid disease, as well as fertility problems and developmental defects in unborn children.

The issue is that UK water companies are not required by law to reduce PFAS until they are deemed ‘high risk’ – by which time, it’s probably too late.

Existing standards allow concentrations of each individual PFAS at up to 10 times the level considered ‘low risk’, which is 10ng/L (nanograms per litre). However, there are potentially thousands of different types of PFAS and they often hunt in packs. Whenever they combine, there are no limits currently in place on total concentration levels.

In the United States they take a much tougher approach. The authorities there have introduced a new limit of four nanograms per litre (ng/L) for both PFOS and PFOA chemicals.

Meanwhile, the EU’s Drinking Water Directive states that 20 widespread PFAS must collectively not exceed 100 ng/L – unacceptable, in our opinion.

How to filter PFAS out of your tap water

According to the UK’s Department for Environment, Food and Rural Affairs (Defra), they take “the risks posed by PFAS chemicals very seriously.” But, whilst they look at “managing risk from PFAS”, as yet, they aren’t testing our drinking water.

So where does that leave you as a consumer? Far from powerless, actually, because the good news is that you can take action yourself to filter PFAS from your drinking water.

Reverse Osmosis

Arguably the best way to remove PFAS from tap water is via reverse osmosis (RO) products. PFAS compounds are plentiful in number but tiny and complex in structure and RO is rare in that it is capable of significantly reducing their concentration in contaminated water.

RO filtration involves using a semi-permeable membrane to separate out PFAS molecules from the good water.

A 2020 American study revealed that a reverse osmosis water filter is the most effective tool for removing PFAS.
The review found that RO water filters, which can easily be installed under most kitchen sinks, were over 90 percent effective at screening out PFAS chemicals.

Activated Carbon Filtration

A less effective but reduced cost approach to removing PFAS contaminants from tap water is via an activated carbon filter. With this method, the water is filtered through beds of porous carbon, which attracts the harmful PFAS molecules. To maintain their efficacy, carbon filters do need replacing more frequently.

According to another 2020 US study carbon filters were, on average, able to remove 73 percent of PFAS contaminants. So, whilst not as effective as RO, carbon is certainly a better-than-nothing option.

What about standard Brita water filters, you may ask? Well, they do use a form of carbon technology and are known to remove some PFAS – but they aren’t specifically designed for this purpose. So, they shouldn’t be your first port of call if you are looking to eradicate the vast majority of PFAS from your drinking water.