In April 2026, EPA released a proposal that, if finalized, would begin the process to potentially regulate the presence of pharmaceuticals in drinking water, by designating them as “Candidate Contaminants.” This proposal is likely to be of significant interest to pharmaceutical manufacturers, given that it entails EPA evaluating, in detail for the first time, potential health risks posed by the presence of pharmaceuticals in groundwater. The proposal may ultimately culminate in EPA promulgating enforceable limits on the presence of certain pharmaceuticals in groundwater.
EPA’s Proposal
In the proposal, EPA noted that “[f]or over a decade” there has been “public concern about the presence of pharmaceutical substances in sources of drinking water,” and identified the issue as “an Agency priority.” Accordingly, EPA proposed inclusion of all pharmaceutical products—broadly defined as any “drug” within the meaning of the Federal Food, Drug, and Cosmetic Act—on Candidate Contaminant List #6.
Listing as a Candidate Contaminant is the first step towards regulation of a substance under the Safe Drinking Water Act (“SDWA”). Every five years, EPA must make a determination as to whether to regulate a Candidate Contaminant. 42 U.S.C. § 300g-1(b)(1)(B)(ii)(I). EPA must regulate a Candidate Contaminant if (1) “the contaminant may have an adverse effect on the health of persons,” (2) the contaminant occurs, or is likely to occur, in public water systems “with a frequency and at levels of public health concern,” and (3) EPA determines that “regulation of such contaminant presents a meaningful opportunity for health risk reduction for persons served by public water systems.” 42 U.S.C. § 300g-1(b)(1)(B)(ii)(II); id. (b)(1)(A). If EPA determines to regulate a contaminant, it would set enforceable limits on the amount of the contaminant that can be present in drinking water, known as “maximum contaminant level.”
As part of its proposal, EPA also released human health benchmarks for 374 pharmaceutical products. The purpose of the benchmarks is to identify levels of pharmaceuticals in drinking water that may present a health risk and thus warrant “additional water monitoring or research.” The specific individual benchmarks are available here.
Potential Implications for Pharmaceutical Companies
As relevant here, the SDWA primarily regulates “public water systems,” and so if pharmaceuticals ultimately become regulated under the SDWA, pharmaceutical companies would likely not have direct obligations under the Act unless they operated such a system. 42 U.S.C. § 300g, 300g-3. Moreover, the SDWA “does not provide a federal right of action for the recovery of compensatory damages,” so public water suppliers would not have a federal statutory cause of action to seek reimbursement for costs spent to treat drinking water that contains pharmaceuticals. Bell v. Lockwood, Andrews & Newnam, P.C., No. 16-10825, 2016 WL 9776140, at *3 (E.D. Mich. Apr. 13, 2016).
That said, listing of pharmaceuticals as SDWA-regulated contaminants could nevertheless have significant implications for pharmaceutical manufacturers. For instance, the SDWA expressly preserves the availability of state-law and common-law remedies, 42 U.S.C. § 300j-8(e), and so it is possible that water suppliers could attempt to recover costs incurred in treating pharmaceuticals in their water supply system from manufacturers under state law or common law. Likewise, consumers of water with pharmaceuticals exceeding a relevant regulatory threshold could attempt to bring state- or common-law claims. Finally, listing under the SDWA may present broader reputational concerns.
Lessons from the EU
The European Union’s regulation of pharmaceuticals in groundwater may be indicative of how regulations in this area might develop in the US. In the EU, under the Water Framework Directive, as recently amended, the list of priority substances identifies specific substances, including several pharmaceutical substances, presenting a significant risk to or via the aquatic environment. Substances included in the list are subject to “environmental quality standards” and their presence must be progressively reduced or phased out. In addition, the Drinking Water Directive requires EU Member States to assess risks in catchment areas for drinking water abstraction points and, where relevant, to monitor pollutants in surface water, groundwater or raw water, including priority list substances. The Groundwater Directive, as amended, also imposes groundwater quality standards for different pharmaceutical substances.
Moreover, the new Urban Wastewater Treatment Directive requires Member States to introduce an advanced wastewater treatment to remove micropollutants (so-called “quaternary treatment”) and requires companies marketing human medicines and cosmetic products to pay for at least 80% of the costs, including investment and operational costs, for the quaternary treatment of urban wastewater to remove micropollutants resulting from products they place on the market and from residues of such products.
Next Steps
EPA is accepting public comment on its proposal until June 5, 2026, and anticipates issuing a final decision by November 17, 2026. Interested parties should consider submitting comments to the agency.