Dishwashers not only need a water supply, but need water under pressure.

So you would need a pressurized tank using a pump from your tanks to the holding pressurized tank.

Theoretically, if the tanks had enough "head" ie, uphill far enough, you might not need a pump, but if you're using rainwater from the roof, there's not going to be enough pressure.

Your washing machine will probably be an issue too. Most solenoid valves found in dishwashers and washing machines require a fair amount of water pressure to operate.

What you should do, and I'd assume building regulations would require is a pressure pump, something like this (I'd assume it would have a tank with a bladder, but this is the general idea:

Here is a link that might be useful: Pressure pump

"Most solenoid valves found in dishwashers and washing machines require a fair amount of water pressure to operate. "

The valves are electric, though they often have a large pressure drop when they are open (they are typically pretty small bore valves).

A bladder type pressure tank should take care of the problem.

This post was edited by brickeyee on Wed, Feb 27, 13 at 12:42

i would contact a mob called TopTanks

they organized a specialized pump for me in a similar situation, they may be able to do the same for yourself.

goodluck

Here is a link that might be useful: water tanks

Dishwasher is a mechanical device which is used to clean dishes and eating utensils. Dishwasher needs both water supply as well as water comes in pressure because it cleans utensils by spraying hot water typically between 55 degree to 75 degree. Here water is rotate from one more rotating sprays arms, which clean the dishes with the cleaning mixture.

Here is a link that might be useful: hiblow hp

This post was edited by JeromeMoler on Thu, Aug 28, 14 at 3:22

Gday i live in Wisemans Ferry in NSW Australia and i am on tank water and brought a new dishwasher its a small bench top one its works great no problems at all the water pressure from the pump is all i needed no extra things the one i got was called a Solo brand i brought it on the net i hope this has help you

I live on tank water with a pump and after going through 3 dishwashers and 3 electrician call outs ive gone back to hand washing. Clothes washing machine works fine.,love to hear how you go.,

Electric/solenoid water valves on dishwashers, washing machines, and ice makers in refrigerators rely on water pressure to both feed the water in and also to shut the flow off (which isn't intuitive to people who don't understand the mechanics of how the valves work). They can fail to close properly if pressure is too low, which results in dripping/seeping/leaking of water into the washer, dishwasher, or ice maker when the water flow is supposed to be off.