New monitoring tools and advanced treatments are offering hope amid concerns about PFAS levels in UK waters. The question is whether regulators will act quickly enough.
PFAS “forever chemicals” are prevalent in the UK’s surface and groundwater, entering rivers and aquifers through industrial effluents, firefighting foams and sewage treatment plants, where they cannot be completely removed. As PFAS persist and accumulate in watersheds, utilities are increasingly relying on proven treatments such as granular activated carbon, low-level targeted ion exchange, and complex mixture reverse osmosis. DWI-driven risk-based monitoring is expanding with clearer reporting and hotspot prioritization.
What are PFAS and why do they matter to UK water?
PFAS (per- and polyfluoroalkyl substances) are a vast family of thousands of synthetic “permanent chemicals” that can withstand environmental damage and persist in the human body for long periods of time. Its durability makes it a long-term concern in public health and environmental management, especially when reaching potable water systems intended to safely supply drinking water.
UK regulators are moving towards clearer oversight, including guidance from the Department of Drinking Water Inspection (DWI) to improve detection and control. The challenges are both technical and economic. Many traditional water treatment methods were not designed to capture these chemicals. Targeted filtration and replacement technologies are increasingly central to reducing exposure and compliance costs, as seen in approaches promoted by the Environmental Protection Agency (EPA) and others.
Where do PFAS enter UK water supplies?
So where do PFAS seep into the UK’s rivers, reservoirs and aquifers? Evidence first points to industrial wastewater, where manufacturing effluents and the use of PFAS-containing products funnel persistent chemicals into nearby water sources. The second major entry point is firefighting foam used at airports and military bases. Wastewater treatment plants also serve as a continuous pathway. PFAS from homes and businesses enters sewer systems, where traditional treatments often cannot remove them and are released into receiving rivers and downstream aspirates.
Monitoring highlights the extent of this presence. Around 80% of surface water samples and 50% of groundwater samples in the UK tested positive for PFAS. Their detection in all fish tested further indicates that they are accumulating within the aquatic ecosystems connected to these water sources across the UK.
How do PFAS travel from source to tap?
Once PFAS enter rivers, reservoirs, and aquifers from industrial effluents, firefighting foams, and wastewater discharges, they can be further transported through leaching into groundwater and runoff into surface waters needed to pump drinking water. PFAS are resistant to biodegradation, so they persist for long periods of time, moving with water flows and gradually accumulating in watersheds and aquifers. From there, the compounds enter the raw water intake and remain through traditional clarification and disinfection steps. Many common processes are not designed to capture these highly stable chemicals, so without targeted treatment, concentrations may be reduced only slightly. If the source is affected, utilities may require special treatment and source control measures to limit migration from the environment to the water supply.
How are PFAS monitored in UK drinking water?
How are PFAS tracked once they enter the drinking water system? In the UK, the DWI oversees monitoring through water company sampling and reporting, designed to quantify PFAS levels and alert to emerging risks in drinking water. The new DWI guidance introduces a risk-based, three-tier system to help utilities prioritize where and how often to test and how to interpret detections.
Companies must also measure 6:2 fluorotelomer sulfonamide alkylbetaine (FTAB), expanding the list of regularly checked substances. To support broader intelligence on precursor chemicals and analytical gaps, utilities must notify DWI of unidentified PFAS detected at levels below 0.01 μg/l.
Beyond treated supplies, the UK’s monitoring program collects data from groundwater, surface water and wastewater sites to map water sources and routes. The regulatory framework may be updated under the Environment Act of 2021 to align with evolving science and practices used by the Environmental Protection Agency (EPA).
How does granular activated carbon (GAC) remove PFAS?
Tracking PFAS across the UK’s drinking water network will help utilities decide when they need to match monitoring and treatment. Granular activated carbon is widely used for PFAS removal because it provides a large number of adsorption sites due to its porous structure and very large internal surface area. As water passes through the GAC bed, hydrophobic PFAS compounds preferentially attach to the carbon surface, reducing dissolved concentrations and improving water quality.
Performance depends on the specific PFAS compounds present, flow conditions, and media loading rate. In controlled studies, GAC has achieved removal efficiencies of over 90% for some PFAS, demonstrating strong potential when properly designed and operated. The system can be customized to target localized contamination profiles by selecting carbon type, layer depth, and contact time. However, there are limits to its adsorption capacity. As carbon approaches saturation, breakthrough occurs and the effluent concentration increases. Therefore, periodic replacement or regeneration is essential to maintain reliable PFAS reduction over time.
When might ion exchange or membranes work more effectively against PFAS?
In what situations are ion exchange resins or membrane systems superior to granular activated carbon for PFAS control in UK drinking water treatment? Ion exchange provides superior performance when contamination is at low concentrations and the PFAS profile is well characterized, as selective binding targets specific ions while passing most of the background chemicals. This is often appropriate for small-scale or modular water treatment upgrades where cost control is important and rapid PFAS removal is required.
Membranes that include reverse osmosis tend to perform better when a broader mixture of PFAS and co-contaminants need to be addressed, resulting in higher overall rejection rates. However, pretreatment may be required to reduce membrane fouling and maintain throughput, which complicates operation. Some designs can add advanced oxidation processes upstream to weaken PFAS compounds and improve downstream capture.
How are PFAS cleaned up in UK groundwater sites?
Cleaning up PFAS at groundwater sites in the UK typically involves a combination of source control and targeted remediation, reflecting the persistence of contaminants and the need to protect drinking water supplies. The study will first map groundwater contamination and then prioritize responses where receptors are most vulnerable.
For PFAS remediation, pump-and-treat systems typically pass the extracted water through activated carbon, particularly granular activated carbon, to capture long-chain compounds and reduce PFAS levels. When field chemistry or PFAS profiles limit carbon performance, ion exchange resins offer higher throughput and can target short-chain materials. Advanced oxidation processes can also be applied as part of the processing train to degrade precursors.
Regulatory authorities such as the Environment Agency can propose emission limits that facilitate compliance-oriented design and verification sampling. In parallel to established methods, innovative treatment solutions such as electrochemical processing and nanomaterial-based filtration are being investigated to improve removal efficiency and reduce waste burden in difficult sites.
How do you build a long-term PFAS risk plan for the UK?
As evidence and exposure pathways evolve, how can the UK’s long-term PFAS risk plan remain reliable? It needs to combine routine monitoring with transparent prioritization. England will monitor and report 2,400 PFAS samples annually across freshwater to track PFAS levels, identify hotspots and assess whether remediation strategies are protecting water supplies.
By 2026, the Environment Agency’s PFAS GIS priority map will be published, allowing local authorities and businesses to adjust their actions and funding according to risk. A broader evidence base will need to follow, including a feasibility study for PFAS monitoring in soil and a full assessment of estuary and coastal contamination by February 2028.
Governance is also important. Collective ownership across government, industry, and the general public supports consistent standards and accountability based on international benchmarks, such as those set by the Environmental Protection Agency (EPA). This structure transforms the PFAS challenge into a path toward a PFAS-free market by 2040, with significant economic opportunities.
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