What Is PFAS in Drinking Water? Limits, Risks, and Testing Methods

PFAS contamination is now one of the most closely watched issues in drinking water quality. If you’re a utility operator, consultant, lab manager, or supplier, you’re likely seeing increased questions about PFAS limits, monitoring requirements, and how testing is actually performed.

Often called “forever chemicals”, PFAS are highly persistent compounds that resist natural breakdown and can accumulate in the environment over time. As regulations tighten across Europe, the UK, and beyond, understanding PFAS—what they are, why they matter, and how they’re measured at extremely low levels—has become essential.

This guide explains what PFAS are, why they are a concern in drinking water, how they are regulated, and the main testing methods currently used to monitor them.

Key Takeaways

PFAS are persistent “forever chemicals” that can enter drinking water sources and remain for long periods.
Regulators are moving toward tighter limits and broader PFAS coverage (including group-based parameters).
Most PFAS monitoring relies on specialist laboratory analysis due to ultra-low detection requirements.
If PFAS are detected, follow-up testing and treatment options may be needed depending on levels and local rules.

What Are PFAS?

PFAS is a large group of man-made chemicals that includes thousands of individual compounds. They have been used since the mid-20th century in a wide range of industrial and consumer applications due to their resistance to heat, water, and oil.

Common uses of PFAS include firefighting foams, non-stick cookware, water-resistant textiles, food packaging, and certain industrial processes. The strength of the carbon–fluorine bond that makes PFAS so useful is also what makes them environmentally persistent.

Once released into the environment, PFAS do not readily degrade and can remain in soil and water for decades.

Why Are PFAS a Problem in Drinking Water?

PFAS are of concern because of their persistence, mobility, and potential health impacts. These compounds can migrate through soil and enter surface water and groundwater sources used for drinking water production.

Scientific studies have linked exposure to certain PFAS compounds with a range of potential health effects. While research is ongoing, the precautionary principle has driven regulators to adopt increasingly strict limits for PFAS in drinking water.

In addition to health concerns, PFAS present operational and reputational challenges for water utilities, particularly as public awareness of the issue continues to grow.

PFAS Regulations and Limits

PFAS Limits in the European Union

The revised EU Drinking Water Directive introduced limits for PFAS that represent a major shift in regulatory approach. Rather than focusing on individual compounds alone, the directive includes group-based parameters designed to capture a wider range of PFAS substances.

If you want to reference the source directly, you can read the EU Drinking Water Directive here: EU Directive (EU) 2020/2184 (Drinking Water Directive).

PFAS in the United Kingdom

In the UK, PFAS regulation is evolving, with guidance informed by international research and regulatory developments. Water companies are increasingly expected to monitor PFAS proactively and to demonstrate an understanding of potential risks within their supply areas.

Although regulatory limits differ between regions, the overall direction of travel is toward tighter control, improved monitoring, and increased transparency.

Global Regulatory Snapshot

Globally, PFAS regulation varies, but many jurisdictions are moving toward lower limits and broader compound coverage. In the United States, the Environmental Protection Agency provides ongoing updates on PFAS and regulatory actions: US EPA PFAS overview.

International bodies also publish health and risk information on PFAS. For an additional high-level reference, see: World Health Organization (WHO) PFAS fact sheet.

How Are PFAS Detected in Drinking Water?

Detecting PFAS in drinking water is technically challenging. These compounds are typically present at extremely low concentrations, often measured in parts per trillion.

Accurate PFAS analysis requires highly sensitive analytical techniques, strict contamination control, and specialised laboratory expertise. Even small sources of background contamination (for example, from sampling materials or lab consumables) can affect results.

Common PFAS Testing Methods

LC-MS/MS for PFAS Analysis

Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is currently considered the gold standard for PFAS analysis. This technique offers the sensitivity and selectivity required to detect individual PFAS compounds at very low concentrations.

LC-MS/MS is widely used by accredited laboratories for regulatory compliance testing and detailed PFAS investigations.

Targeted vs Non-Targeted PFAS Analysis

Targeted PFAS analysis focuses on a defined list of known compounds, providing precise quantification for regulatory reporting. Non-targeted methods aim to identify a broader range of PFAS substances, including unknown or emerging compounds.

Both approaches have a role to play, depending on monitoring objectives, budgets, and regulatory requirements.

On-Site vs Laboratory PFAS Testing

At present, most PFAS testing is carried out in specialist laboratories due to the complexity of the analysis. While research into field-based screening methods is ongoing, laboratory analysis remains essential for confirmatory results and compliance monitoring.

Who Needs to Test for PFAS?

PFAS testing is relevant to a wide range of stakeholders, including drinking water utilities, industrial water users, environmental consultants, and regulatory bodies.

In many cases, monitoring programmes are being expanded to include PFAS as part of routine water quality assessment—particularly where there is known risk from industrial activity, firefighting foam use, or legacy contamination.

What Happens If PFAS Are Detected?

If PFAS are detected above guideline or regulatory levels, further investigation is typically required. This may include confirmatory testing, source identification, and assessment of potential mitigation measures.

Several technologies, such as granular activated carbon (GAC), ion exchange, and membrane processes (including reverse osmosis), are commonly used to reduce PFAS concentrations in drinking water. The right option depends on PFAS type, concentration, site conditions, and operational constraints.

The Future of PFAS Monitoring and Regulation

PFAS regulation and monitoring requirements are expected to continue evolving as scientific understanding improves. Many experts anticipate broader compound lists, lower detection limits, and more comprehensive reporting obligations.

For water utilities and suppliers, staying informed about PFAS developments—and maintaining defensible monitoring and reporting processes—will be critical to long-term compliance and public confidence.

Conclusion

PFAS represent a complex and long-term challenge for the drinking water sector. Their persistence, potential health impacts, and increasing regulatory focus mean that understanding PFAS limits, risks, and testing methods is now essential.

As monitoring requirements expand and treatment technologies advance, PFAS management is likely to remain a central issue in water quality for years to come.

FAQ

What does PFAS stand for?

PFAS stands for per- and polyfluoroalkyl substances—a large group of man-made chemicals used across many industries and products.

Why are PFAS called “forever chemicals”?

Many PFAS are extremely persistent because they do not readily break down in the environment, which means they can remain in water and soil for long periods.

Can drinking water utilities test PFAS on-site?

Most PFAS testing is still performed in specialist laboratories because detection limits are extremely low and strict contamination control is required. Field screening methods exist in some contexts, but laboratory analysis remains essential for confirmatory and compliance results.