In the 1987 case Gwaltney of Smithfield, Ltd. v. Chesapeake Bay Foundation, Inc., et al., the U.S Supreme Court ruled on whether citizen suits under the Clean Water Act could be brought against alleged violators for past infractions or only ongoing violations. The court held that citizens may seek civil penalties in federal court only if they can make a good-faith allegation of continuous or intermittent violation - that is, a reasonable likelihood that a past polluter will continue to pollute in the future. This decision was based on language within the act itself which authorizes citizen suits "against any person ... who is alleged to be in violation" of certain provisions of this law (emphasis added). Therefore, it was determined by majority opinion written by Justice Byron White that allegations limited solely to wholly past violations do not fall into this category and thus are insufficient grounds for such lawsuits.

In the dissenting opinion for GWALTNEY OF SMITHFIELD, LTD. v. CHESAPEAKE BAY FOUNDATION, INC., et al., Justice Brennan disagreed with the majority's interpretation of the Clean Water Act (CWA). He argued that it allows citizens to sue polluters even if they are not currently violating their permits but have done so in the past and may do so again in future. According to him, this is because Congress intended for citizen suits to supplement government enforcement efforts under CWA and deter potential violators from non-compliance through penalties imposed by courts on previous violations. The majority's ruling would undermine these objectives as it could allow a company that has violated its permit multiple times without penalty to escape liability simply by temporarily coming into compliance during litigation process.