Regulatory Developments

Rules Governing Pesticide Products in Drinking Water

If the operator of a public water system (PWS) uses a registered pesticide product to treat the water, which federal law takes precedence—the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) or the Safe Drinking Water Act (SDWA)?

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The answer is neither—both laws must be fully complied with; moreover, meeting the requirements of either law should not interfere with meeting the requirements of the other. Generally, compliance with FIFRA is subject to more federal oversight; what’s more, states may impose additional requirements on federally registered pesticide products. Also, implementation and enforcement of the SDWA is typically the work of the states, but the EPA retains the power of overseeing state programs. Moreover, registration of a pesticide product and compliance with FIFRA regulations covering a pesticide device does not mean that a PWS operator is meeting the requirements of other environmental and public health protection statutes, including the SDWA, or vice versa.

These are several of the points covered in a new EPA document, Quick Guide for Disinfectant Products for Drinking Water Use by Public Water Systems. The purpose of the guide is “to provide clarity for applicants seeking approval for disinfectant products for drinking water use.”


Pesticide products are governed by FIFRA and must be registered (licensed) by the EPA unless explicitly exempted. There is no general exemption from registration for pesticide products that are applied to PWSs. Pesticide devices (i.e., an instrument or contrivance, other than a firearm, that is used to destroy, repel, trap, or lessen the severity of any pest) are not subject to FIFRA registration but must meet FIFRA requirements regarding misbranding and also must be produced in an EPA-registered establishment.

All nonexempt pesticide products applied to PWSs must meet the full set of registration requirements. Registration can be a complex and prolonged process, and the EPA urges applicants seeking registration to first contact the appropriate product team in the Agency’s Office of Pesticide Programs (OPP) to learn which data and labeling requirements they will need to submit. Submissions may include efficacy, chemistry, acute toxicity, chronic toxicity, and environmental fate studies. Once these studies are complete, the applicant prepares a registration package according to OPP’s Pesticide Registration Manual and submits it to the OPP.

Upon approval of the application, registrants must meet any required state pesticide registration provisions. States may have stricter standards than those prescribed in federal regulations. Also, the Quick Guide indicates that FIFRA registration for drinking water use should be obtained before submission to a state, tribe, or territory for product approval under their drinking water laws.


The EPA does not register or approve disinfection products under the SDWA but, instead, imposes requirements on each regulated PWS to deliver water that meets specific standards to persons served by the system. Each PWS must determine which product or combination of products to use to meet federal and any applicable state, tribal, or territorial drinking water requirements.

Also, EPA’s drinking water rules provide requirements for disinfecting water supplies. Applicants with such products should consult the Surface Water Treatment Rule (SWTR), the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), and the Ground Water Rule (GWR) for treatment requirements. These rules provide criteria for establishing inactivation by different disinfectant products when applied to surface water or groundwater. Such products include chlorine, chloramine, chlorine dioxide, ozone, and/or ultraviolet light (UV).

While requirements under the SDWA do not prohibit the installation of a given technology, applicants should consult with the relevant state, tribe, or territory regarding procedures for approving new technologies in PWSs under state, tribal, or territorial law. States, tribes, or territories may have standards beyond those prescribed in the SDWA and its implementing regulations.

Again, after satisfying all pesticide requirements under FIFRA, applicants should consult with the relevant state, tribe, or territory to determine the procedures, if any, for product approval for drinking water use in that state, tribe, or territory.