Concern over the presence of per- and polyfluorinated substances, more commonly known as PFAS, in our drinking water is growing. These substances, which include PFOA, PFOS, GenX, and more, do not break down for decades and have been linked to kidney and testicular cancer, high cholesterol, low fertility, thyroid issues, and a decrease in the effectiveness of vaccines in children. (Source Source)
On June 23, 2023, chemical giant 3M Co. announced that it would settle a collection of lawsuits over its role in contaminating U.S. drinking water with PFAS. The magnitude of the settlement, at least $10.3 billion to around 300 communities in the United States, demonstrates how seriously communities and regulators are taking the harmful effect of PFAS in drinking water. (Source)
We still do not have a reliable method of removing PFAS from our drinking water. This means that our priority must be to limit the emissions of PFAS at the source. The four main sources of PFAS in our drinking water are firefighting activities, industrial sites, landfills, and wastewater treatment plants. The last three sources are considered “point-source” pollution, meaning that they are located in a fixed geographic area and emit pollution into the environment. Access to accurate data on point-source PFAS pollution is essential to manage this issue. (Source Source)
The current state of PFAS point-source pollution monitoring
In the United States, point-source water pollution (pollution from a fixed source that does not move) is managed by the National Pollutant Discharge Elimination System (NPDES) as defined by the 1972 Clean Water Act (CWA). The NPDES is a system that issues permits to facilities that discharge wastewater into the waters of the United States. These permits set pollution limits for effluent discharge from the facilities. The majority of states manage their own NPDES programs. (Source Source)
Discharge limits are set based on state-level regulations which set acceptable limits for pollution in drinking water. In cases in which states do not have jurisdiction, the NPDES program is managed by the federal government, which enforces maximum allowable limits for PFAS in drinking water. Not all states currently regulate PFAS in their drinking water, however. (Source)
The table in Fig 1 shows the patchwork level of the allowable PFAS level in drinking water by state. The map in Fig 2 shows the number of facilities with PFAS data in the NPDES data in 2023.
Why would there be NPDES data from a state which doesn’t regulate PFAS in drinking water?
This is usually due to the relationship between state governments and tribal governments. If a facility discharges effluent into tribal waters, the NPDES is managed by the federal government. For instance, Idaho does not regulate PFAS in drinking water. However, this facility in Idaho has a NPDES permit managed by the federal EPA, because it discharges into Nez Perce tribal waters.
Why would there be states with PFAS limits for drinking water with no NPDES data?
Future availability of PFAS data
The EPA has proposed a nationwide regulation for six PFAS in March 2023 that will set a limit on the amount of the chemicals allowed in drinking water. (See Fig 3) Assuming there are no major delays, the proposed limits will affect local drinking water systems in 2026. We can expect, therefore, an increase in the number of facilities whose NPDES permits include limits on PFAS discharge. As the number of these permits increases, stakeholders across the United States will have increased visibility into the facilities’ PFAS discharges. (Source Source)