Earlier this year, scientists at UC Davis released a report entitled “Addressing Nitrate in California’s Drinking Water, With a Focus on Tulare Lake Basin and Salinas Valley Groundwater.” Perhaps you have heard about this report already, even read bits and pieces of it, or maybe you have read it in its entirety. The 80-page main report is accompanied by eight technical reports, and all are available at the website groundwaternitrate.ucdavis.edu. To attempt to summarize hundreds of pages in a one-page newsletter article would be impossible but with this article, I will attempt to summarize why this report was generated, some key findings, and some food for thought for us to consider now and in the future.

In 2008, the California Legislature passed a law that required the State Water Resources Control Board (Water Board) to investigate groundwater nitrate levels in the Tulare Lake Basin and the Salinas Valley. Essentially, legislators wanted answers to some questions. How much nitrate is in the groundwater? How did it get there? What can we do to reduce it? How much will it cost?  To help answer these questions, the Water Board contracted with UC Davis to get some answers. The UC Davis findings will be included as part of a larger report that the Water Board will provide to the Legislature.

The UC Davis report states that there are two major problems caused by nitrate in groundwater. The first relates to public health because drinking water nitrate levels above 45 milligrams per liter exceed the California Department of Public Health’s level for safety. The study found that 254,000 people in the study areas are at risk of having drinking water nitrate exceeding this level. Cropland was reported to be the source of 96 percent of the human-generated nitrate found in groundwater. The second problem caused by nitrate in groundwater is the cost of cleaning it up. Cleanup measures could include water treatment and/or new wells and could have costs of $20-35 million per year. The report went on to say that addressing the problem will require a multipronged approach of providing safe drinking water, reducing sources of contamination, collecting data, and providing funding to support all of these needs.