Ag Drainage Connects Us All

posted by Ingrid Gronstal on Thursday, May 16, 2019

The influence of agricultural practices on drinking water quality continues to be of paramount concern for Iowa’s environmental and public health. Over the last few years, much has been made of the urban/rural divide and industrial/municipal versus agricultural contributions to nutrient loading in our waterways. Setting those larger points of contention aside for the moment, let’s focus on drinking water supplies in rural Iowa.

Dr. Chris Jones noted in his May 8th essay on agriculture tile drainage that increased tiling results in higher baseflow to streams, which is the “main hydrological driver of stream nitrate.” Dr. Jones also noted that “[n]itrate-nitrogen is an important contributor to . . . impairment of water resources and drinking water in Iowa,” linking to coverage of a recent report released by IEC and the Environmental Working Group. Our report found that thousands of private wells used for drinking water across Iowa contain unsafe levels of nitrate.

Dr. Jones is correct that agricultural practices can and do have negative effects on rural drinking water supplies, which harm human health. The EPA’s legal limit for nitrate in drinking water is 10 ppm (parts per million), and recent studies point to increasing health risks, such as elevated cancer risks and birth defects, with rates of just 5 ppm.

This is not simply a case of negative outcomes for downstream urban communities or loss of aquatic life in the Gulf of Mexico. Our recent private well study highlights the widespread consequences of nutrient pollution in rural Iowa farming communities. Iowa’s failure to regulate nutrient pollution fails farmers and the communities in which they live.

The state has relied on the Iowa Nutrient Reduction Strategy, which contains a suite of practices the farmers can use to reduce nutrient pollution in our water. Because the strategy is voluntary, we are not on track to reduce nutrient loading to targeted levels. Moving to a mandatory regulatory approach would even the playing field for farmers and ensure drinking water protection for citizens across the state.

As a native of a small Iowa town, I internalized the importance of caring for our neighbors long ago. The water resources in our state belong to everyone, and the harm from nutrient pollution is felt in every community and every county. We need scientists like Dr. Jones and the researchers at Environmental Working Group to help us understand and expose our water quality challenges.

IEC does not share this information to be Chicken Little. Instead, by alerting Iowans to these troubling data trends, we can empower our family, friends, and neighbors to talk with their local leaders and push for smart regulation that will be protective of both farmers and their rural neighbors.

Get more facts on nutrient pollution in Iowa's water at

  1. drinking water
  2. nitrate pollution
  3. water quality

About The Author

Ingrid Gronstal served as Water Program Director with the Iowa Environmental Council from 2018 -  2022. She has many years of experience in water policy, most served as the Compliance Specialist at the University of Iowa Utilities and Energy Management. She previously worked as a consultant ... read more