Runoff and/or leaching can occur when pesticides are carried off the application site into water such as rivers, lakes and streams, wells, storm sewers, or into groundwater. Runoff/leaching can occur when too much pesticide is applied or is spilled on the surface, too much rainwater or irrigation water occurs in a short period of time, or highly water soluble pesticides are used.
To gain a better understanding of how, where and why water runs off and how to prevent pollution read the following UNL publications: