Well I have just started watering the garden, I planted most of the summer vegies in september/october and this meant that they got a bit of rain to get established before summer really hit. I was busy over summer and apart from sporadic watering everything produced ok and then dried out and died which was perfectly fine. But because we are heading into autumn and I'v planted winter vegies such as beetroot, leeks, broccoli as well as some late bush beans iv been forced to begin regular watering. Now I'm doing my best to conserve water, heavily mulching new plantings, leaving gaps between watering to drive the plants roots deeper and only watering tree's and perrenials when they are newly planted. Despite this I end up watering fairly frequently in any given year so I have been looking at buying a water tank.
The water bill tells me that for 1000 litres of water we have to pay around $1.80 including waste water charges. If the 5000 litre tank I'm looking at costs $1500 then we would have to use 833,000 litres to pay the tank back. Now I'm not sure how many litres I use from year to year but some rough calculations tell me it could take a few decades to pay it back at current prices. So I'm going to compromise, I'm looking at a second hand tank that holds 1800 litres and should cost a few hundred dollars, after a year of using that I'm going to reconsider how big a water tank I really need for the garden.
Increasing ones autonomy from centralised infrastructure can be a time sonsuming and expensive process. The benefits and potential pitfalls of relying on our current system for nessecities should be weighed before one rashly decides to plunge headlong into self sufficiency.