The Clean Water Act and the Agricultural Exemption

Any conversation about water quality in Iowa inevitably boils down to the fact that the largest industry in Iowa – agriculture – is not subject to most water quality regulations. Why is that? What is unique about the agriculture industry?

It all boils down to one complicated law: the Clean Water Act. Let’s dig in to better understand what the Clean Water Act covers, what it doesn’t, and where we stand today.

The Federal Water Pollution Control Act of 1948 was the first major law to address water pollution in the United States. By the 1970s, two-thirds of the country’s lakes, rivers, and coastal waters had become unsafe for fishing and swimming. It was common for untreated sewage to be dumped directly into open water. The Cuyahoga River in Ohio infamously caught on fire in 1969, likely due to an oil slick with a low enough flashpoint to be ignited by a spark from a passing train. Growing public awareness and concern about the state of the U.S. waters led to sweeping amendments to the Federal Water Pollution Control Act in 1972. As amended in 1972, the law became commonly known as the Clean Water Act (CWA).

The CWA established the basic structure for regulation of pollutant discharges into the waters of the United States and gave the Environmental Protection Agency (EPA) authority to implement pollution control programs.

The CWA regulates point sources of pollution through the National Pollutant Discharge Elimination System. The system requires permits for all discharges to surface waters from point sources, which are defined as “discernible, confined, and discrete” sources of pollution discharge. Examples include discharge points from factories, chemical manufacturers, wastewater treatment plants, and oil refineries. The lofty goal of this permit program, as laid out in the name, was to eliminate discharges into waterways by 1985.

 “Agricultural storm water discharges and return flows from irrigated agriculture” are expressly excluded from the point source definition and permit program of the CWA. This is commonly referred to as the “CWA agricultural exemption.” The exemption has also been applied to discharges from tile lines, despite there being little difference between a tile pipe discharge and an industrial pipe discharge.

Due to this exemption, most agricultural pollutants are considered non-point source (NPS) pollution. The EPA says that “NPS pollution generally results from land runoff, precipitation, atmospheric deposition, drainage, seepage, or hydrologic modification.” This leaves a major gap in the coverage of the CWA, especially in an agricultural state like Iowa. With 92% of nitrogen and 80% of phosphorus in Iowa waterways coming from nonpoint sources, the vast majority of nutrient pollution is unregulated.

This gap means that steps to reduce agricultural pollution are almost entirely voluntary. While taxpayers spend millions of dollars to regulate point sources, upgrade wastewater treatment facilities to comply with water quality standards, and enforce those standards, farmers are asked to voluntarily implement practices that reduce pollution, sometimes at the cost of production, even when their competitors do not. It’s easy to see why voluntary adoption of practices is not at the scale and scope necessary to address our water pollution problems.  

Non-point sources are purportedly regulated differently because there is theoretically no “point” (i.e., a discharge pipe) at which to measure the quality of water coming from a particular source. However, we now have better information and more understanding of hydrology, watersheds, and how to target conservation practices on the landscape. The Iowa Environmental Council is exploring options to develop smart regulations that protect water quality, level the playing field for farmers, and ensure everyone has skin in the game to improve the water that we all share.

1. clean water
2. drinking water
3. public health
4. water quality