Millymollymandy wrote:I was just looking at the price of 100,000 litre tanks and worked out at our current usage (let's say 200m3 including garden p.a.) it would take us about 49 years to break even.
I can't see us ever getting enough rainfall to fill the whole thing twice a year though!
You'd be surprised MMM, ours only fills in the winter and we've never had to buy water despite having very long droughts every summer.
Rainfall profiles are really important: we don't get any rain from May to Sept, temperatures are consistently high, so we so need to water the plants more often and we need daily showers. Factoring this all in means we need a much bigger cistern than someone in Northern Europe.
The capture area is important too, if it was just our roof we'd never fill the cistern, but as we capture rain off a much bigger area, which is sized for our cistern, it's always full as summer arrives.
One other addition we are going to have this summer is a small cool-pool to sit in and cool down . It will built in cocciopesto (lime mortar with crushed pottery/hydraulic lime and filled crushed bricks), and be filled each morning via a submersible 12v and a PV panel. It'll have a read/float switch, so stop once it's full. In the evening we'll turn a tap to empty the cool-pool and the water will then be used to irrigate plants. It's taken us a while to work out a system, which doesn't require electricity to fill and enable us to reuse the water. I can't wait .