Field rinsing can eliminate the problem of chemical contamination of the soil or well water if the sprayer is cleaned in the same place for several years. If rinsate can be used as spray mix makeup water for another spraying job, it can be stored. Be sure to label the container and store in a secure area where other pesticides are kept. Do not store mixed pesticide or rinsate for more than a few days. Spray until the tank is empty - that should be the end of the job if the sprayer load was calculated properly and the sprayer was calibrated correctly.
Good planning can eliminate a big disposal problem.
Start the sprayer pump and circulate rinse water through the tank rinse nozzles for 1-2 minutes to thoroughly wash the tank walls and sprayer lines. Spray the rinsate onto an approved crop. If the amount of mixed pesticide was figured correctly for the field, the active chemical from the washing operation should be applied to the field being sprayed. Repeat step 2 two more times. Most of the active chemical should now be removed from the spray tank.