Good idea: rain collection from roofs holds water
I have installed a simple, cost-effective system here in Spain, and have collected an average of 30,000 litres annually over the last 13 years, despite dry weather. The system consists of guttering piped to a 10 cubic-metre tank, coupled to a small pump that delivers the water to the house. A simple valve system allows mains or collected water selection.
Anybody with basic DIY skills can install such a system. I suspect Mr O’Donnell underestimates the amounts of water that households could collect in Ireland. Self-sufficiency in water consumption is attainable for most families.