One way to track potential future environmental regulations that may affect your company is to monitor the Contaminant Candidate List (CCL) and the Unregulated Contaminant Monitoring Rule (UCMR). For instance, the Environmental Protection Agency (EPA) included per- and polyfluoroalkyl (PFAS) as a broad classification on the 2022 CCL.
CCL, UCMR, and Future Environmental Regulations
While both the CCL and UCMR are under the Safe Drinking Water Act (SDWA), what is regulated under the SDWA can lead to limitations under other environmental regulations.
As defined by the EPA,
- The CCL is a list of drinking water contaminants that are known or anticipated to occur in public water systems and are not currently subject to the EPA drinking water regulations. The CCL is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations but are known or anticipated to occur in public water systems. Contaminants listed on the CCL may require future regulation under the SDWA.
Roughly speaking, the CCL involves more research and initial screening. We are currently on CCL 6. The CCL informs future UCMR regulatory determinations.
- The EPA uses the UCMR to collect data for contaminants (no more than 30 in each cycle) that are suspected to be present in drinking water and do not have health-based standards set under the SDWA. The SDWA requires that, once every five years, the EPA issue a list of unregulated contaminants to be monitored by public water systems (PWSs).
Roughly speaking, the UCMR involves more sampling and testing. We are currently on UCMR 6.
Among the potential pollutants getting attention are pharmaceuticals and microplastics.
Draft CCL 6
On April 6, 2026, the EPA issued notice of the draft Sixth Contaminant Candidate List, which includes 75 chemicals, 4 chemical groups (disinfection byproducts [DBPs], microplastics, PFAS [that contain one of three specific chemical structures], and pharmaceuticals), and 9 microbes. The EPA seeks public comment on the draft CCL 6 and the process used to develop the draft CCL 6. The EPA will consider all information and comments received in response to this notice of availability for determining the final CCL 6 (Source: Federal Register).
Getting most of the attention are two potential contaminants: pharmaceuticals and microplastics.
Environmental Concerns Associated with Pharmaceuticals
In an April 2, 2026, announcement, the EPA states that Pharmaceuticals, including antidepressants, hormones, antibiotics, and other drugs that enter water systems through human waste and improper disposal, are also being prioritized as a group for the first time. The EPA is simultaneously releasing human health benchmarks for 374 pharmaceuticals, giving states, Tribes, and local water systems a critical new tool to assess risk and take action when drug residues are found at concerning levels.
For decades, there has been concern about how pharmaceuticals may be entering and affecting the environment. Pharmaceuticals disposed of in the garbage can end up in landfill leachate. If they are flushed in the toilet or if they are unabsorbed in the body, they can end up in a wastewater treatment influent and, potentially, effluent.
While there have been studies in 2009 and 2014 on influent and effluent samples, there are currently no Maximum Contaminant Levels (MCLs) for pharmaceuticals.
Environmental Concerns Associated with Microplastics
In the April 2, 2026, announcement, the EPA stated that Microplastics are tiny plastic particles that have been detected in human blood, breast milk, and organs and are now officially on the EPA’s radar as a drinking water priority. This is the first time the agency has elevated microplastics to the CCL as a contaminant group, unlocking focused research and potential future regulation.
The Biden Administration attempted to address big-picture plastic concerns when it released “The Draft National Strategy to Prevent Plastic Pollution” in 2023.
In listing microplastics on the Draft CCL 6, the EPA states, “There are currently data gaps that require further research before the Agency can fully understand the health risks associated with microplastics in drinking water.”
Microplastics are defined as plastic particles less than 5 millimeters or 0.2 inches in length, many of which are often not visible to the naked eye.
While widely present in the environment and, according to some recent studies, found in human organs and tissues, the health effects of microplastics are not fully understood.
The “MAHA (Make America Healthy Again) Report, Making our Children Healthy Again” lists several potential health concerns associated with Microplastics, including acting as endocrine disruptors.
The CCL and UCMR are a preview of possible future regulatory limits in other environmental regulations. With the attention that is being paid to microplastics, it would not be surprising if there is some regulatory pressure in the near future to develop plastic management plans.
Environmental Expertise
Managing the changing environmental risk landscape requires constant diligence and, at times, legal and technical advice. Dragun can assist with technical advice. If you need assistance or have questions, you can contact Jeffrey Bolin, M.S., at 248-932-0228, Ext. 125.
Alan Hahn drafted this blog. Alan has an undergraduate degree in Environmental Studies and completed a graduate program in Environmental Management. He has worked in environmental management for more than 45 years. He has written hundreds of blogs and articles. His published work includes Michigan Lawyers Weekly, Detroiter, Michigan Forward, GreenStone Partners, Manure Manager Magazine, Progressive Dairy, and HazMat Magazine.
Jeffrey Bolin, M.S., reviewed this blog. Jeff is a partner and senior scientist at Dragun Corporation. He is a published author, a frequent speaker, and an expert witness. His expertise in environmental due diligence, PFAS, vapor intrusion, and site assessments has led to projects in the US, Canada, and overseas. See Jeff’s Bio.
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