Introduction
In April 2024, the EPA finalized the first-ever national drinking water standards for per- and polyfluoroalkyl substances (PFAS), setting Maximum Contaminant Levels (MCLs) for six individual PFAS compounds. These enforceable limits — as low as 4 parts per trillion for PFOA and PFOS — represent a seismic shift in compliance obligations for public water systems nationwide. For utilities in the Mid-Atlantic and beyond, the question is no longer whether PFAS monitoring is necessary, but how to build an instrumentation strategy that meets these new requirements on time and within budget.
What the EPA PFAS MCLs Require
The final rule establishes individual MCLs of 4 ppt for PFOA and PFOS, and 10 ppt for PFHxS, PFNA, and HFPO-DA (GenX). Additionally, a hazard index of 1.0 applies to mixtures of PFHxS, PFNA, HFPO-DA, and PFBS. Public water systems serving more than 10,000 people must complete initial monitoring within three years, while smaller systems have five years. Systems that detect PFAS above MCLs must implement treatment and achieve compliance within the regulatory timeline.
These limits are extraordinarily low — parts per trillion detection requires analytical methods (EPA Method 533 and 537.1) that push the boundaries of current laboratory capabilities. Utilities must plan not only for sample collection and lab analysis but also for the supporting instrumentation infrastructure that ensures treatment systems operate effectively.
The Role of Instrumentation in PFAS Compliance
While PFAS concentration itself is measured through certified laboratory analysis rather than online analyzers, a robust instrumentation strategy is essential for treatment optimization and compliance documentation. Utilities implementing granular activated carbon (GAC), ion exchange, or reverse osmosis treatment for PFAS removal need continuous process monitoring to ensure these systems perform as designed.
Total organic carbon (TOC) analyzers play a critical role in GAC treatment monitoring. TOC serves as a surrogate indicator for GAC bed exhaustion — as organic carbon breakthrough increases, PFAS breakthrough typically follows. Continuous online TOC measurement allows operators to predict when GAC media needs replacement, avoiding both premature changeouts that waste money and late changeouts that risk PFAS exceedances.
Turbidity monitoring upstream and downstream of treatment processes helps verify particle removal performance, which is particularly important for membrane-based PFAS treatment systems. Pressure transmitters and flow meters across treatment trains ensure hydraulic performance remains within design parameters, directly affecting treatment contact time and removal efficiency.
What Utilities Should Be Doing Now
Even before treatment installation begins, utilities should conduct a thorough assessment of their existing monitoring infrastructure. Key steps include identifying all potential PFAS sampling points in the distribution system, evaluating whether existing sample taps and access points meet the contamination-free requirements for ultra-low-level PFAS sampling, reviewing SCADA and data logging capabilities to ensure compliance data can be captured, stored, and reported in the required formats, and assessing whether current TOC, turbidity, and flow instrumentation can support treatment process monitoring.
Many utilities will discover gaps in their monitoring infrastructure that need to be addressed before treatment systems come online. Retrofitting sample points, upgrading data acquisition systems, and installing additional process monitors takes time — utilities that begin this assessment now will be better positioned to meet compliance deadlines.
How Emergent Energy Can Help
As an instrumentation integrator with deep experience in water treatment applications, Emergent Energy helps utilities navigate the instrumentation requirements of PFAS compliance. Our services include sampling infrastructure assessment and design, TOC and turbidity analyzer specification and installation, SCADA integration for compliance data logging, and coordination with certified analytical laboratories for sample chain-of-custody workflows.
We work with leading analyzer manufacturers including Hach and Sievers to specify instruments matched to each utility's treatment approach and compliance requirements. As a COSTARS contract holder, we can streamline procurement for Pennsylvania public water systems.
Contact our team at 215-645-7141 or visit emergentenergy.us/contact to discuss your PFAS monitoring strategy.