Is an exemption from US groundwater regulations a loophole or a noose?

In the United States, the Safe Drinking Water Act (SDWA) regulates most groundwater used for drinking water. The Act covers most urban areas but because it does not cover small water systems, it implicitly exempts nearly half of those living in rural America. In large measure, monitoring required by the SDWA has illustrated the prevalence of naturally occurring arsenic in groundwater in concentrated areas throughout the country. Even though many in Congress seem aware of this threat and have, indeed, supported more stringent arsenic standards, Congress, on the whole, has failed to update the SDWA to cover those water systems left unprotected by the Act. Conventional political science theory suggests that effective congressional oversight depends on Congress creating both active (e.g., hearings and commissioned studies) and passive oversight mechanisms (i.e., citizen suits and opportunities for constituent feedback). In this case, Congress had, in fact, created sufficient tools to detect a serious problem but, having identified it, nevertheless failed to respond. Why? In exploring Congress’s inaction, we find something unexpected: the structure of the SDWA has created perverse incentives not only for unregulated water systems but also for regulated systems to push to keep exempted water systems unregulated. The outcome is that those outside of the SDWA’s protections remain outside and continue to drink contaminated water by the glass full. So, while Congress created a loophole, it may have inadvertently tied a noose.