PFAS water testing: why utilities are under growing pressure to get it right

By Element

Jenny Davies and Marie Armstrong from Element's environmental testing team discuss how the UK's PFAS Plan, AMP8 investment programmes and evolving DWI expectations are changing the way water companies approach monitoring, sampling and compliance.

With the publication of the government's new PFAS Plan, forever chemicals have become a serious operational concern for water companies across the sector. Monitoring expectations are moving in one direction. Guidance is shifting in line with international expectations. Testing programmes are being developed.

What utilities are grappling with now is harder: How much trust can be placed in the data being generated? How confident can they be in how it was collected? And will the monitoring approach they have today hold up when regulators look more closely tomorrow?

There is also a change in what utilities expect from testing laboratories. Turnaround time still matters. But the question being asked more often now is whether the data behind a major decision can be defended if it gets challenged.

What does the PFAS Plan mean for water companies?

The PFAS Plan signals the direction of travel for regulation and monitoring in the UK. While it does not introduce immediate new limits for water companies, it makes clear that government, regulators and industry will need a stronger understanding of where PFAS is present, how it moves through the environment and how exposure can be reduced over time.

For water companies, that means increased focus on monitoring, evidence gathering and understanding potential contamination pathways. The emphasis is moving beyond simply identifying PFAS and towards building a clearer picture of risk across catchments, assets and water sources.

As expectations continue to evolve, many organisations are reviewing whether their current monitoring programmes will provide the level of confidence and insight required in the years ahead.

How are AMP8 and DWI changing PFAS monitoring?

DWI guidance is already changing what happens on the ground. PFAS monitoring is becoming routine rather than reactive, and it is increasingly tied to risk assessments that take in the full picture. Source water quality, catchment activity and potential contamination pathways are all becoming more important considerations when designing monitoring programmes.

Practically speaking, we are seeing a push for lower detection thresholds, cleaner audit trails, and a better understanding of where contamination might come from before anyone acts on it.

As water companies develop PFAS monitoring and management strategies through AMP8, there is growing focus on generating data that can support long-term investment decisions, withstand regulatory scrutiny and provide a clear understanding of potential risks across networks and catchments.

One of the biggest changes is the move towards more risk-based monitoring. Rather than treating every site in the same way, utilities are increasingly assessing local factors such as catchment history, historic industrial activity, source water vulnerability and known contamination risks. This helps monitoring programmes become more targeted and allows resources to be focused where they are likely to have the greatest value.

Another challenge is consistency. Monitoring programmes often run for many years, and data collected today may be used to support future operational or investment decisions. Sampling methods, reporting limits and laboratory processes all need to remain consistent enough that results can be compared over time with confidence.

PFAS contamination is an emerging issue

Collecting and transporting the samples correctly matters as much as the analysis. PFAS testing for water samples is lab-based. Samples are taken at source, transported under controlled conditions, and analysed in a controlled environment. That setup helps keep variability down.

But producing a number is not the whole job.

As reporting thresholds become lower, utilities are also paying closer attention to contamination controls. One of the biggest challenges is that, below a certain point, the issue is less about instrument sensitivity and more about controlling background contamination well enough to trust the result.

From our experience, this is where many organisations are focusing their attention. The discussion is increasingly shifting away from simply detecting PFAS and towards understanding whether contamination controls and reporting limits are robust enough.

When monitoring data could influence significant operational or capital investment decisions, confidence in the methodology becomes just as important as the result itself.

That is a genuinely easy risk to underestimate. PFAS is already present in a huge range of materials that people handle without thinking twice. There needs to be an awareness around everyday items. Things like waterproof clothing or packaging can introduce contamination without you realising. You must have a proper process and appropriate measures in place when testing to avoid cross-contamination.

The controls that matter are straightforward but unforgiving: PFAS-free containers, no fluoropolymer materials anywhere in the process, properly managed sample handling, field blanks run with every batch. A problem introduced at this stage does not stay at this stage. It travels through to the result.

These controls need to be applied consistently, regardless of how routine a sample may appear.

Understanding current best practice

Meanwhile, PFAS contamination risks do not disappear simply because a monitoring programme is established.

Inconsistency in sampling approaches is also becoming a real problem for interpretation.

As reporting thresholds become lower and laboratories are expected to detect increasingly smaller concentrations of PFAS, methods that were acceptable a few years ago may no longer provide the level of confidence or consistency required.

Ultimately, a positive result is only useful if there is confidence in how the sample was collected, analysed and reported. As monitoring programmes expand, utilities are placing greater emphasis on producing data that is technically defensible and comparable over time.

Detection is not enough on its own. Confidence in the methodology, consistency across the programme, and the ability to interpret what the numbers mean in operational terms are all part of making better decisions.

Accreditation is more complicated than it looks

Another issue we need to overcome is different sample types.

You can't just test "water".

Groundwater, surface water and treated water all behave differently in analysis. A laboratory has to have validated its methods against each matrix on its own. A general water accreditation does not stretch across all three automatically.

That distinction has become more significant as monitoring programmes cover more ground. When data needs to be comparable across different sites, different asset types, and long-running monitoring programmes involving multiple water matrices, the details of what a lab is actually accredited for start to matter a great deal.

You've found PFAS - what's next?

Even when everything we have discussed so far is in place, finding PFAS does not come with a simple next step.

Treatment is achievable. Activated carbon filtration is the standard approach in water treatment. PFAS is captured, and the captured material is then destroyed at very high temperatures. But that process introduces its own monitoring requirement. Emissions need to be checked to confirm the contamination is actually being destroyed rather than moved somewhere else.

This is part of why PFAS has gone from a peripheral technical concern to something with genuine operational weight across the water industry. Identification is one piece of the picture. Understanding what a result means, deciding what needs to happen in response, and implementing mitigation properly are equally significant parts of the work.

The direction coming from both the PFAS Plan and DWI guidance is clear. Monitoring expectations are increasing, and utilities are under growing pressure to demonstrate that decisions around PFAS risk are supported by reliable, defensible data. For many organisations, the challenge is no longer whether to monitor for PFAS, but how to build programmes that can adapt as expectations continue to evolve.

As regulation develops and scrutiny increases, the ability to produce genuinely reliable results will matter more, not less.

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