Over the past 20 years, the science of groundwater chemistry has evolved through a convergence of technical advancements and regulatory reprioritization. In 1986, the understanding of contaminated groundwater both from a regulatory and hydrochemical perspective was in its nascence. Concerns about groundwater quality have grown with demand for limited, marginal-quality groundwater resources and an increase in our understanding of the human and ecological effects of many substances. The profile of these concerns has been raised by several prominent water quality crises, including the West Bengal/Bangladesh groundwater arsenic issue and problems at several high-profile industrial sites in the United States.

The technical response to the regulatory environment has included changes in the characterization of water in the field, analysis in the laboratory, and interpretation in the office. Field sampling techniques have evolved to more quantitatively assess in situ well chemistry using instrumentation and more quantitative sampling techniques. Advances in laboratory instrumentation have allowed routine detection of more compounds at lower levels. These lab advances have allowed the development of water quality standards for some chemicals at levels not routinely measured 20 years ago. Finally, the wide application and use of computing has streamlined the processing, delivery, and presentation of chemical data. While these computing and instrumentation advances have increased productivity, they also have created a heightened impression of certainty that may be unwarranted.