and approaches to water. As the population spread into larger and more suburban areas, the costs associated with water treatment increased and the benefits were less apparent than in initial projects. Financial pressures also limited resources for new projects. By the 1930s, there was an increasing role of the federal government, not in the development of local water systems, but rather in the testing of particular problems and providing support. The federal government stepped in to create standards for systems, impacting health standards and delivery technologies. For the most part, however, water and wastewater systems in place today remain similar to their early incarnations. At the time, attitudes about medicine and health again shifted, as new medications and patient treatments became better understood. The strong focus on preventive medicine of the medical community was rapidly replaced by an interest in medical treatment of the diseased individual, a trend that is only beginning to be reversed today. Again the role of public health in water and sanitation diminished and remains relatively low in industrialized nations.
One of the disadvantages of a permanent, highly capitalized set of systems, such as in the United States and elsewhere, is their lack of resilience—the inability to address emerging problems. Following the postwar years, water pollution became complicated by nonpoint sources and groundwater contamination. These problems could not be addressed easily by means of large treatment plants located near a river. Such structures have proven to be essential in dealing with point pollution, but they could not necessarily address other forms of pollution.
In summary, the water and sanitation systems developed in the 19th and 20th centuries were strongly influenced by social norms and prevailing scientific theory. Little was known about the etiology of disease, the presence of pathogens in water, filtration or treatment, or environmental protection—and those aspects were not incorporated into early systems. Later advances still failed to amend the limitations of future systems, becoming larger and less adaptable. Public health played a decreasing role over time, whereas maintenance and replacement of water systems became the bigger issue as original infrastructure passed the century mark.
The future of water and sanitation requires a sustainable and adaptable system. The original design never regarded the need to address environmental contamination that was not from a point source. Historic trends are critical to the current situation, as the infrastructure and limitations owing to public health and cultural ideas of sanitation have shaped the current path, making it difficult to change direction. Nevertheless, optimism prevails as public opinion shifts back toward the value of preventive medicine and public health, the preservation of the environment, and investments in public infrastructure.