WASHINGTON, D.C. — The Environmental Protection Agency on September 9 announced a new drinking water study that uses non-targeted laboratory methods to scan samples for a far wider range of chemicals than standard tests can catch, including pharmaceuticals, PFAS compounds and more than 1,000 other potential contaminants. The research is intended to improve understanding of what may be present in finished drinking water.
“We have heard loud and clear that Americans are concerned about potential unknown pollutants lurking in their drinking water. The Trump EPA is committed to getting to the bottom of this, so that Americans can feel confident about the safety of their drinking water,” said EPA Administrator Lee Zeldin. “EPA’s state-of-the-art study will shed light on this issue and complement the actions we are already taking under the Safe Drinking Water Act. What we learn will provide clarity and peace of mind while guiding the agency’s continued efforts to Make America Healthy Again.”
Conventional methods typically look for a short list of known chemicals one group at a time. Non-targeted analysis (NTA) uses mass spectrometry to detect a much larger set of compounds in a single sample and then matches those signals against a reference library.
Health and Human Services Secretary Robert F. Kennedy Jr. framed the project as long overdue.
“Americans have a right to know what is in the water they drink,” Secretary Kennedy Jr. said. “EPA is going to search for pharmaceuticals, PFAS, and other contaminants that have gone undetected — and give Americans the truth about what is in their water.”
EPA’s own fact sheet for the study fills in the technical picture. Researchers plan to collect drinking water from several locations in different metropolitan areas and screen those samples against a custom library of more than 1,400 emerging contaminants.
That library, current as of September 2026, includes more than 1,000 pesticides and pesticide metabolites, more than 250 pharmaceuticals and personal care products, more than 70 PFAS chemicals, and additional emerging contaminants.
The agency said NTA can confirm that a chemical appears to be present. It does not, by itself, measure how much is there. Results are also expected to feed a database of unidentified chemical signals for later work.
Under the Safe Drinking Water Act, EPA still has to show that a contaminant occurs at levels of concern, that it may have an adverse health effect, and that regulation would provide a meaningful opportunity for health risk reduction.
The research sits alongside two other drinking water actions the agency rolled out earlier this year.
In April, EPA released its draft Sixth Contaminant Candidate List, known as CCL 6 — a set of enforceable standards. It is the first step in the statute’s five-year cycle for unregulated contaminants: a roster of substances known or anticipated to occur in public water systems that may eventually require regulation. The draft includes 75 individual chemicals, nine microbes and four chemical groups — microplastics, pharmaceuticals, PFAS and disinfection byproducts.
The pharmaceutical group is defined broadly, covering substances that meet the definition of a “drug” under the Federal Food, Drug, and Cosmetic Act. EPA also released human health benchmarks for 374 pharmaceuticals. which can enter sewers and, later, source water through human waste and improper disposal, including leftover antidepressants, hormones, antibiotics and other medicines.
In June, EPA proposed the Sixth Unregulated Contaminant Monitoring Rule, or UCMR 6. If finalized, public water systems would sample for some 30 or so chemicals during a window running from 2028 through 2030.
The proposed UCMR 6 list includes seven ultrashort organofluorine compounds, among them several PFAS such as PFMOAA, PFEtS, PFPrS, PFPrA, TFMS and TFA, plus bistriflimide; three pesticide metabolites; 13 semivolatile organic compounds; and seven purgeable organic compounds.
Examples on the list include 1,2,3-trichloropropane, chlorothalonil, DEET, metribuzin, trifluralin, naphthalene and 2,4- and 2,6-dinitrotoluene. Large systems serving more than 10,000 people would pay their own analytical costs. EPA would cover the lab costs for smaller systems.
All community and non-transient non-community systems serving more than 10,000 people would monitor for the substances, along with systems serving 3,300 to 10,000 people and a representative sample of still smaller systems, subject to funding and laboratory capacity.
Author: Mario Lotmore
