As new housing estates are planned, instead of using fencing to divide house blocks Im sure we could use 2 metre tall, 300mm wide plastic water tanks. These are long lasting and can become a shared resource for the homeowners.
All water is diverted into the fence line and residents access half of whats stored. Sloping blocks fill tanks below, but use water from above them.This can work for most new housing but is dependant on terrain. Tanks can be isolated from each neighbours allotment and occasionally water pumps may be required. Imagine the amount salvaged in each estate and the water saving.