What alcohol concentration makes bathroom cleaner "disinfecting"? There are many do-it-yourself cleaner solutions out there, using a combination of vinegar, alcohol (in a "cheap vodka" concentration), dish soap, baking soda and essential oils. I like these recipes for two reasons, first for cost and second for health (sometimes my toddler helps me clean his bathtub, and I wouldn't want him to use too harsh stuff).

However, many of these recipes claim to be "disinfecting", and as far as my understanding goes, alcohol has that effect, as has stuff that offsets the pH-level (such as the acidity of vinegar). But given that this stuff is just sprayed onto the surface, can a mixture of 2 parts water 1 part vodka really be concentrated enough to be "disinfecting"? And if you mix baking soda and vinegar, won't that bring you closer to a neutral pH, i.e. offset any "disinfecting powers"?

Is there some sort of guideline as to how much alcohol/other agent should be in the final solution for it to be of good use in cleaning a bathroom?
According to this Center for Disease Control document:  


  Ethyl alcohol (70%) is a powerful broad-spectrum germicide and is considered generally superior to isopropyl alcohol. Alcohol is often used to disinfect small surfaces (e.g. rubber stoppers of multiple-dosemedication vials, and thermometers) and occasionally external surfaces of equipment (e.g. stethoscopes and ventilators).  


Although 70% alcohol is ideal, another CDC article states that it can be effective at 50%.  According to this article:  


  In the healthcare setting, "alcohol" refers to two water-soluble chemical compounds—ethyl alcohol and isopropyl alcohol—that have generally underrated germicidal characteristics.  FDA has not cleared any liquid chemical sterilant or high-level disinfectant with alcohol as the main active ingredient. These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria; they also are tuberculocidal, fungicidal, and virucidal but do not destroy bacterial spores. Their cidal activity drops sharply when diluted below 50% concentration, and the optimum bactericidal concentration is 60%–90% solutions in water (volume/volume).  


So, alcohol has certainly been shown to be a powerful, broad-spectrum antimicrobial agent, though not at the dillution you proposed. I would just use the straight vodka if it were greater than 50% alcohol, or probably beter (cheaper) yet would be denatured alcohol if that's available where you live.