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Its a good idea to wash your veggies, but this is not the most effective method. Bath them in warm water, dont wash them under the faucet.

Despite the fact that I had my reasons to end the SuppVersity "True or False" Series back in the day. The popularity of the corresponding articles that appear from time to time as SuppVersity Classics on Facebook does yet tell me that you wont be mad at me, if I revive it and try to tackle a statement Ive overheard in one of those infamous gym conversations between two ladies on the cross-trainer: "I always wash those pepper extra thoroughly, you know... tomatoes are among the veggies with the highest amounts of pesticides on them." Answer lady two: "Ha, you dont really believe the pesticides are on the outside of the tomatoes only, do you? They are in the tomato. Washing them will at best remove some of the dirt on their skin!"

True or False: "Its useless to wash your peppers."

False - I was surprised, when I realized that the answer to this True or False item was much easier to find than I had thought. It took me a while, though, before I found a study that analyzed data from more than just one vegetable variety, but the basic answer,  i.e. "No, its not useless to wash your peppers - quite the contrary!" popped up right in my first cursory database search.

Figure 1: Amount of ethylenebisdithiocarbamates and chlorpyrifos on selected vegetable (µg/kg) before and after washing; the figure above the bars indicate %-change from pre to post washing (Chavarri. 2004; Randhawa. 2007)

If you look at the data of two studies I selected more or less randomly (see Figure 1) you will yet see that the effectiveness of the "wash away the pesticide approach" depends on both, the type of vegetable and the type of pesticide. With a mean total endusulfan reduction of >20% it should however be absolutely obvious that not washing your veggies would be wreckless.
I mean, I shouldnt have to tell you to that its unquestionably healthy not to be exposed to the full load of 24µ/kg chlorpyrifos and 1,626µg/kg ethylenebisdithiocarbamates (both have carcinogenic effects in humans; cf. Houeto. 1995, Josephson. 2005), from the tomatoes - specifically in view of the fact that 5.% of the tomatoes that are sold in the EU exceed the contemporary pesticide limits (Nasreddine. 2002) and would thus contain way more of these hazardous substances to begin with.

Aprospos washing! How do you do that?

You dont know how to wash veggies? Well, I obviously cant tell you what the absolute optimal way is, but what I can tell you is how scientists washed the specimen that were used in the studies the data in Figure 1 is based on: They placed the veggies in a dish or a clean lavatory with warm tap water and cleaned them with "gentle rotations of the hand" (Randhawa. 2007), before they grapped a conventional paper towel and blotted them dry.

Figure 2:  Illustration of the processing steps in Chavarri et al. (2007).

Thats similar to what you do? Great, and you know what, I would bet thats not the only similarity between yourself and the average scientist. Just like you, scientists dont eat all their veggies raw. Consequently, both Chavarri et al. as well as Randhawa et al. conducted additional analyses of the pesticide content of their veggies after the produce had been blanched (the peppers were roasted, not blanched), peeled, pureed (Chavarri. 2004; see Figure 1) and cooked or peeled and cooked (Randhawa. 2007), respectively.

Figure 3: Relative ethylenebisdithiocarbamates and total endosulfan levels (in % of baseline) after washing, peeling, blanching / cooking & co. (Chavarri. 2004; Randhawa. 2007)

As you can see in Figure 3, each of these processing steps lead to a further reduction of pesticides. For the initially highly intoxicated asparagus, for example, even the last traces of pesticides ended up in the cooking water. If you would now decide to recycle the water for a soup or whatever, all your efforts to rid yourself of the pesticide would have been in vein.

References:

• Chavarri, M. J., Herrera, A., & Arino, A. (2005). The decrease in pesticides in fruit and vegetables during commercial processing. International journal of food science & technology, 40(2), 205-211. 
• Houeto, P., Bindoula, G., & Hoffman, J. R. (1995). Ethylenebisdithiocarbamates and ethylenethiourea: possible human health hazards. Environmental health perspectives, 103(6), 568.
• Keikotlhaile, B. M., Spanoghe, P., & Steurbaut, W. (2010). Effects of food processing on pesticide residues in fruits and vegetables: a meta-analysis approach. Food and Chemical Toxicology, 48(1), 1-6.
• Nasreddine, L., & Parent-Massin, D. (2002). Food contamination by metals and pesticides in the European Union. Should we worry?. Toxicology letters, 127(1), 29-41.
• Randhawa, M. A., Anjum, F. M., Asi, M. R., Butt, M. S., Ahmed, A., & Randhawa, M. S. (2007). Removal of endosulfan residues from vegetables by household processing. Journal of Scientific and Industrial Research, 66(10), 849.