U.S. PFAS reporting methods may miss over half of drinking water contamination

How reporting methods distort PFAS data

Researchers at Texas Christian University analyzed the EPA’s January 2026 dataset, which includes monitoring data for 29 types of PFAS across approximately 10,000 water systems. Of 1.86 million individual test results, about 98% fell below minimum reporting limits (MRLs) and were recorded as zero for aggregate reporting.

The study’s statistical models estimated PFAS concentrations in these below-limit samples, generating 500 estimates per value. The models suggested that conventional reporting methods capture only 44% of the average concentration of 25 PFAS types in community water systems.

The discrepancy arises because values below MRLs—often labeled “<MRL”—are treated as zero rather than as concentrations somewhere between zero and the limit. This approach excludes nearly all test results from aggregate data, skewing perceptions of contamination levels.

Implications for utilities and regulators

The EPA monitors PFAS due to their association with cancers, reproductive issues, hormonal disruptions, and other health risks. However, the study argues that current reporting practices may obscure these risks by failing to account for below-limit concentrations.

Lowering reporting limits for specific PFAS types, such as PFOA and PFOS, improved the accuracy of conventional reporting methods. This suggests that regulatory adjustments could lead to more precise data—but also stricter compliance requirements for water utilities.

The study recommends agencies publish details about which chemicals were tested, their reporting limits, and the frequency of below-limit results. This transparency could help utilities and researchers identify gaps in testing and prioritize areas for further analysis.

What this means

Lazyfounder analysis — our interpretation, not reported fact.

For founders and operators in water testing, environmental monitoring, or public health, this study highlights a critical blind spot in PFAS regulation. Current reporting methods may create a false sense of security by excluding below-limit results from aggregate data, even though these values could still pose health risks. Startups developing more sensitive testing technologies or statistical modeling tools could address this gap, offering utilities and regulators a clearer picture of contamination levels.

For chemical manufacturers and water utilities, the findings signal potential changes in how PFAS data is collected and reported. If the EPA revises its reporting limits—especially for high-risk compounds like PFOA and PFOS—operators may face stricter compliance requirements and greater scrutiny of below-limit results. Proactively adopting more precise testing or data modeling could mitigate risks and improve readiness for regulatory shifts.

Key takeaways

• Regulatory reporting standards for PFAS may significantly underestimate exposure risks, affecting compliance strategies for water utilities and chemical manufacturers.
• Founders in water testing, environmental monitoring, or public health tech can address gaps in below-limit PFAS data using statistical modeling or improved testing methods.
• Changes in reporting limits—such as those for PFOA and PFOS—can improve data accuracy, signaling potential shifts in EPA standards that operators may need to prepare for.

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