Pesticides are made up of various chemicals and are used to reduce plant damage due to pests and to control growth of unwanted plant species. Handle and dispose of pesticides properly to avoid risking contamination that could affect the water supplies and health of others.

Pesticide containers should be kept dry and clear of activities that might knock over a jug or rip open a bag. Pesticide storage areas should be downslope and as distant from drinking water sources as possible to provide reasonable assurance source water will not be contaminated. Separation should be greater if the site has sandy soils or fractured bedrock near the land surface. If possible, reduce the amount and types of pesticides stored. Keep pesticide storage areas locked and provide signs or labels identifying the cabinet or building as a pesticide storage area. Pesticides should be stored in sound, properly labeled, original containers. Steel shelves are easier to clean than wood if a spill occurs, and smaller container shelves should have a lip to keep containers from sliding off. Provide pallets to keep large drums or bags off the floor and keep pesticides separate to prevent cross-contamination. Use containment for large bulk tanks to contain spills. Conduct mixing and loading on impermeable surfaces away from drinking water sources; immediately clean up any spills. Properly recycle or dispose of pesticide containers. 

Following these management proceduresgreatly reduces the possibility of drinking water contamination. Effects of pesticide contamination vary depending on the toxicity of the pesticide and the amount of exposure. If large amounts of pesticide enter a water supply, as can happen with a spill or accident, acute health effects are possible. However, low levels of contaminants in drinking water can also be harmful to people and animals through chronic exposure.