You know, it's next year (2013) that the Department of Water Affairs predicted that Gauteng’s water demand would begin to outstrip supply.
That's not someone else's problem: it's yours, because the first (and most effective) thing the authorities will do to reduce demand, is make water too expensive to be casual about. So it will hit your household bottom line.
So what are you doing about it?
You have two options: increase your own water supply (harvest rainwater), or reduce your demand (be frugal about using it, and reuse your water). (You can sink a borehole, maybe, but that just adds to the problem in the medium term, since underground aquifers are already highly stressed, and it's just a matter of time before that option is either taxed or in some other way becomes unviable).
If you know that up to 50% of water supplied for urban and domestic use is consumed in landscapes such as office parks and residential gardens, there's a clue right there about how you could make a difference. Add to that the fact that 90% of household water leaves the home as wastewater, and using greywater on your garden becomes a no-brainer.
Greywater comes from sources such as bathtubs, showers, washing machines etc, where no meat residue is present. Of the wastewater leaving the home, about 60% is can safely be used for flushing toiletsand watering the garden. I haven't gone into the business of replumbing the shower into the loo, but I have redirected the shower into a greywater system for the garden.
So what about the soap? Well, since my garden is looking good on it, its not necessarily a bad thing:
Grey water contains nitrogen and phosphorous which can be used by certain plants as nutrients.
The soapy nature of grey water can sometimes act as a pest repellent.
I wish I could say my greywater system is maintenance-free. It's not, but if I spend an hour on it a week, that's a lot, so it's not a big deal. And I haven't turned on the garden tap since I installed it. That's got to be a good thing.