Read my comments properly - I referred to comparison with Coke & similar. A better comparison, which neither you nor Ivo made, is the petro-chemical industry, which are similarly complex from extraction, refining all the way to delivering petrol to you. 
But that's aside from the fact SA companies don't know how to operate in a naturally competitive environment. Giving them water would be disastrous - we'd have the most expensive water among public or private suppliers anywhere in the world.
Back to Coke, etc being a putative supplier. Literally anyone can become a small-scale water supplier by buying commercially available systems the same as desalination technology and filtering and purifying tap or borehole water (not sure about the latter's quality, though, but it would be drinkable). Coke's logistic system is very dissimilar from mains water supply. Assuming desalination, electrical/telecoms suppliers like Neotel and Telkom have an advantage over and more experience than cellular.