To optimize my time as much as possible, I would like to know if I can simply put them in water and leave them there for a while. This would help if there are lots of fruits and vegetables to be washed. Would this help to remove bacteria and pesticides on them? How long should they be soaked in minimum to really be effective? How long in maximum to avoid effects on taste and nutrition? How long before they get spoiled? Should I put something into the water?
Washing fruit and vegetables in water is less an exercise in sterilisation and more a case of simply washing off any mud or debris. Soaking in still water does nothing to clean, well, anything really. Even if you sterilise the water and container, the fruit itself will still be teeming with bacteria which would be perfectly happy to multiply in stagnant water.
Simply wash the fruit/veg under a briskly running stream of water to remove any major dirt. There is unlikely to be anything terrible on fruit or vegetables in any case, assuming you have a healthy immune system.
If you really want to reduce bacterial load, the only solution is thorough cooking.
Washing/soaking in a 3:1 water/vinegar mixture can eliminate 98% of bacteria. 1 However, there is not a distinct improvement over washing under running water.