May 12, 2026

expert reaction to study of PFAS in London tap water

A study published in Environmental Sciences: Advances looks at the occurrence of PFAS in London drinking water. 

Prof Oliver Jones, Professor of Analytical Chemistry at RMIT University in Melbourne, said:

“I wonder if ‘PFAS in tap water within safe limits’ would make a great headline, but, while the results only apply to London, it is great to see a positive news story about PFAS for once, and I hope it is widely reported. This is a well-conducted, thorough study from an experienced group, so people can be reassured that the data are accurate.

“Some people may wonder why we should accept any PFAS in our water at all. This is not totally unreasonable, but it is worth bearing in mind just how small these measurements are. Modern analytical equipment is a technological marvel and can detect almost anything anywhere, but just because something is present does not automatically mean it is a problem. A nanogram per litre (ng/L) is one part per trillion. For context, 1 trillion seconds is roughly 31,700 years (and no, that’s not a typo). So, if we measure 10 ng/L, it’s like measuring 10 seconds per 31,700 years. That is an incredibly small amount of actual PFAS, and it is unlikely to cause any harm, especially as most PFAS are unreactive.

“It’s also worth remembering that PFAS is a category, not a specific compound. There are various definitions, but each gives you several thousand possible compounds. It is not helpful to class everything that meets some broad definition as the same risk. For example, we don’t ban all mushrooms just because some are poisonous.

“Another question we may want to ask is, if, as these results show, tap water has very low concentrations of PFAS, then drinking water is not a major route of exposure for the UK population to PFAS. If this is the case, then what are the major sources of PFAS exposure to the population (if any)? If food or airborne particulates contain more PFAS than water does, we would need to focus on these exposure pathways rather than water to reduce PFAS exposure. This is the sort of information we need to assess the risk, and it’s something I think the government may want to consider in future.”

Dr David Megson, Reader in Chemistry and Environmental Forensics, Manchester Metropolitan University, said:

“This is a great piece of research, PFAS in tap water has been a major source of concern for the public, especially in London. This research uses citizen science, so involved local communities and individuals to test their own tap water. The research is well aligned with regulatory standards, it hopefully provides the public with some reassurance that our tap water is regularly monitored and adheres to our current regulations.

“One minor limitation is acknowledged by the authors, and that is the lack of testing on ultrashort PFAS (such as TFA), this is not commonly tested for in the UK but is now starting to be regulated in Europe. The scientists tested a wide number of households and also performed repeat measurements in some households which gives added confidence in the data.

“This manuscript provides key data which backs up my own beliefs that drinking tap water is now not a major source of legacy PFAS exposure. Regulators and water companies have done a brilliant job over the last few years to improve our drinking water quality with respect to PFAS. The same concerted effort is now needed in other areas, such as food and other everyday items that contain PFAS. The environmental audit committee (EAC) have recently called for action in this area, so I hope government are listening. With the right regulation and support in place, we can make a difference.”

‘Occurrence of PFAS in municipal drinking water: a participatory case study in London, UK’ by Alexandra K. Richardson et al. was published in Environmental Science: Advances at 12 noon UK time on Tuesday 12 May. 

DOI: 10.1039/d6va00076b

Declared interests

David Megson: “none”

Prof Oliver Jones: “My group is active in PFAS research. I have previously received funds from the Environment Protection Authority Victoria and various Australian Water utilities for research into environmental pollution, including PFAS.”