Gravity (Indirect) Systems
With a Rainstream gravity (indirect) system the captured water is filtered down to 120 microns after being pumped from the system's primary storage tank to a header tank located at a high point within the building being served. Water from the header tank is distributed to the point of use via gravity, with a back-up function that ensures that the water supply is maintained even during a power failure.
The availability of standard (one pump) and duty stand-by (two pump) configurations makes Rainstream gravity systems suitable for a wide variety of applications. The water levels in the tanks are monitored electronically so that fresh mains water can be added to prevent the system running dry, should the rainwater volume fall below a predetermined level.
Pressure (Direct) Systems
These systems do not include a header tank. Instead an electronic control system monitors the demand for water and pumps it directly from the main storage tank to the appropriate outlet. The control system also measures the water level in the main storage tank and imports fresh water if required to prevent the system running dry.
Pressure systems save space within the building by eliminating the need for a header tank and can provide water at a greater pressure than a gravity system. The water is filtered down to 120 microns, and again, both standard and advanced systems are available with one and two pumps respectively.