There is little likelihood that chlorpyrifos will migrate to groundwater. However, direct application to sandy soils, low in organic matter, or over shallow groundwater should be avoided. Predictions about pesticide behavior in soils are made cautiously, since soil type, pH, moisture, organic matter, and temperature may alter the persistence of pesticide residues. Chlorpyrifos disappears quickly in water and on plants when compared to soil. Most water and plant residues are gone within a week.
Sunlight hastens the breakdown of chlorpyrifos.