Despite common belief, even organic produce carries certain controlled levels of pesticides. Studies show that scrubbing with a gentle brush under running water will better clean and purify the surfaces of the fruits and vegetables you eat. This is much more effective that washing with water alone.
Something you should be aware of is that produce coated in wax actually hold onto residue even better than those without.
The best way to know what kinds of pesticides are used on your produce is to buy from a local farmer, whom you will be able to ask specific questions.