What’s in Your Drinking Water? U.S. EPA Takes Aim at Microplastics

In response to growing concerns about the presence of plastic in the human body and the many unanswered medical and scientific questions surrounding its effects, the U.S. Environmental Protection Agency (EPA) has proposed adding microplastics to its list of drinking water contaminants under review.

This is a comprehensive regulatory process that may take time before it directly impacts drinking water utilities. Still, the proposal represents a significant step by the federal government to better understand a pressing public health question: what, exactly, are plastics doing to us?

There is also increasing scrutiny of how much plastic we encounter in our daily lives and where it ultimately ends up.

Consumers today are more informed and discerning than ever. They want to understand how the products they buy - from food and clothing to household goods - are manufactured as well as where they come from.

So, why aren't more people asking those same questions about their drinking water infrastructure?

In the water sector, the phrase “out of sight, out of mind” is all too familiar. Drinking water systems are largely buried underground and tend to go unnoticed until something breaks. However, that mentality appears to be changing as we are seeing growing public concerns about what cannot be seen with the naked eye.

At a recent EPA roundtable, U.S. Health and Human Services (HHS) Secretary Robert F. Kennedy, Jr., pressed for greater clarity on what more needs to be understood regarding microplastics. Dr. Alicia Jackson, Ph.D., director of Advanced Research Projects Agency for Health (ARPA-H), an agency within HHS, offered a direct response:

“We simply don't know the specific microplastics that are going to each part of our body. Whether that is polypropylene, polyethylene, polyvinyl chloride, PET, there are so many different types of microplastics of different size and scale, they go to different parts of our body, from the brain to the mitochondria, and the fastest route we have is to understand which of those microplastics are causing the most harm and focus on those as number one. Focus the most resources on those. That is exactly what we are starting with here.”

The key term here is “polyvinyl chloride,” which is more commonly called PVC. Plastic PVC pipes are used in many drinking water systems in the U.S. and Canada.  Vinyl chloride is the primary chemical in PVC, and it is undergoing federal scrutiny through the Toxic Substances Control Act.

A $144M Initiative to Understand the Risks of Microplastics

Vinyl chloride has also drawn increased attention from regulators. It is a flammable and hazardous substance, and in 2023 it was involved in a train derailment in East Palestine, Ohio, where more than 1 million pounds were released and later burned.

In response to that incident and longstanding concerns raised by environmental and public health advocates, the EPA initiated a risk evaluation of vinyl chloride under the Toxic Substances Control Act (TSCA). These evaluations are comprehensive and can take years to complete, meaning conclusions are still forthcoming.

PVC is now under an enhanced federal spotlight as HHS will attempt to combat toxic microplastics. During the roundtable event, HHS announced that was investing $144 million into a program called STOMP - Systematic Targeting of MicroPlastics – that will be a phased program to identify where microplastics are going in our bodies and to determine which are the most harmful.

This research initiative is long overdue. Announcing the effort, Secretary Kennedy emphasized:

“We can’t treat what we cannot measure; we cannot regulate what we don’t understand. … Together, we’re going to define the risk, build the tools, and act on the evidence regarding microplastics.”

Public confidence in drinking water depends on trust, in both the quality of the water itself and the integrity of the systems that deliver it. As researchers work to define what microplastics are doing to us, communities deserve to know what their pipes are made of. The science is catching up, the known and unknown risks continue to increase, and the infrastructure choices we make should reflect that.