stimated 50% of all water pollution in the United States now comes from nonpoint sources.
Because nonpoint pollution sources are difficult to pin down by the time pollution events or conditions have been identified, the legal and regulatory approach to such pollution at the federal level has historically focused on attempting to control the condition of "input use and management practices" (Helfand & House, 1995, p. 1024). The technical difficulties of regulating nonpoint pollution help explain why, in 2000, the Environmental Protection Agency characterized such pollution as the most significant source of water pollution in the U.S. and the most difficult to regulate (Hale, 2001).
While the theory behind attacking sources rather than consequences appears to be sound, problems of cost efficiency and fairness routinely come to the fore where legal enforcement of clean-water mandates is concerned. To the degree sources of pollution can be identified, use of incentives on the part of input controllers of such pollution, such as farmers, has been recommended as a regulatory option. Another approach that has been recommended is the imposition of taxes on the kinds of "inputs" of contaminants that become pollution effluents. However, controversy is a potential in many situations. For example, if several sources of pollution are implicated along a river but each polluting entity has different levels of input into the river and instruments for measuring such levels are limited in capacity, then placing a "uniform effluent tax will not achieve the social optimum," or fairness (Helfand & House, 1995). That is, the smaller polluters will be subsidizing the tax burden that might more fairly go to the larger polluters.
Accordingly, regulatory incentives that are linked to inputs (origins of pollution) rather than effluents (the pollution itself) have been considered a fairer option, especially if regulators have a realistic picture of input...