Installing a rain tank/reusing the grey water from the washing machine is something I have been meaning to do for awhile at our place. Not very high on the list given the amount of rain lately but one day!

http://www.homegrownevolution.com/2009/ ... urces.html

No sustainable future channel!?

Paul Kennett has done this: Paul's rainwater tanks.

We've just bought a house which has one downpipe not connected to anything, just watering the path, so I think rather than extend it to find the nearest stormwater I might put a tank under it and a hose to the garden.

I've got a couple of 200l barrels that I have been meaning to feed rain water from the roof into for watering the garden, I don't think I'd be keen on washing machine water for the garden though.

How high off the ground do I need to put the tank to get decent pressure for watering? I have an irrigation system that I have to turn the sprinkler head thingies down for mains pressure, so I am wondering if pressure from a rainwater tank will be enough pressure to drive them if I turn them on full.

I tried it a home a few years ago with a 200 litre polythene drum. Had it sitting on a stand about 1m above ground level and water only dribbled out of the hose at low pressure - certainly wouldn't power a sprinkler. Need height for good head. Also make sure its well sealed and has a filtration system otherwise it will soonfill up with gunge and block the outlet.

grey water is fine for the garden as long as it goes in fresh, and you use natural soaps etc.

DO NOT LET GREY WATER SIT!

cant stress that enough, it's fine running straight out into a soakfield in teh vege patch etc, but not into a containment tank for use later on. Run it through soak field at a rate that will disperse it withing 1 hour of entering, and preferably through a sand/silt layer of 70-100mm before any actual 'garden' (basically, dig it 200+mm down and put sand in first).

To get water pressure you need volume+hight. Tall skinny tank=better tha low wide tank etc. And a decent fall height from tank to garden as well. Or, get a 12 volt bilge pump

My system was roofwater from a garage - not greywater.

We did have a greywater watering system we installed at a bach my parents used to have in the Marlborough Sounds. Used a dripline similar to Thorgs description to water some lemons and grapes and stuff till the possums got them.

undergroud irrigation should not need too much presure.

http://www.transportect.co.nz/IRRIGATION.html

as for presure , its in luddite units but may help

http://www.keidel.com/mech/pressure-head.htm