Rainbank - a household water harvesting system ...

Excerpt from Rainbank.com.au:

RainBank is an automatic controller for rainwater harvesting.

RainBank is produced by Davey Water Products, Australia's leading designer and manufacturer of water transfer pumps and pressure systems for the rural, domestic, industrial, pool and spa markets.

Incorporated into the design of new homes or retrofitted to existing properties, RainBank controls the water supply for toilet or laundry applications by automatically switching the water source from the domestic mains to rainwater when a demand is sensed and rainwater is available in the storage tank.

RainBank is the first product to use rainwater as the water supply for toilet and laundry applications in the metropolitan area and control it automatically. It can save up to 40% of a household's drinking water supply which is normally used in these applications, thereby helping conserve Australia's precious water resources.

How it works:

When a toilet is flushed or a washing-machine begins to fill the RainBank system detects this demand and automatically checks to see if there is sufficient water in the rainwater storage tank.

If there is sufficient rainwater then RainBank switches the supply to this source and completes the demand cycle. Once the demand cycle is complete RainBank automatically switches off.

If the rainwater supply is depleted at any time during a demand cycle or prior to a demand cycle, RainBank provides mains water to fulfil the demand. In the case of a power failure, RainBank automatically supplies mains water as the backup.

See - Rainbank.com.au.