All produce, whether it's conventional, organic, or from your own garden, in a peel or labeled "pre-washed," needs to be washed.
Wash just prior to consumption, with clean hands and under cool running water. Avoid commercial soaps and sprays; there is no evidence of their effectiveness, and they might even leave unwanted residues. Some people create their own concoctions of water mixed with vinegar, apple cider, salt, or hydrogen peroxide in varying combinations. But clean running water will remove most, though not all, of the pesticides and herbicides on your produce. To my knowledge, nothing available and safe to use is capable of removing all the bad stuff.
For certain fruits and vegetables, such as grapes and leeks, a water bath (wash, drain, and wash again) is necessary. For leafy vegetables, such as spinach and swiss chard, a thorough soak and rinse in the colander is more suitable. Firmer produce such as cucumber, melon, squash, citrus fruits and potatoes require a veggie brush to remove dirt, chemicals, bacteria, and insects from grooved surfaces. Remove the bruised or damaged outer layer of the produce and wash carefullyespecially critical if produce is eaten raw.
Bottom line, if you want to eat produce with fewer contaminants, buy local and organic, and wash it with cold water.