Rainwater Harvesting Solutions. My business is collecting rainwater from your roof. The water can than be used for: Watering plants, Washing car/Windows, Flushing your toilet, Washing machine use and more. the West of Ireland would yield approx 1131mm of rain per year, most of this rain is unused and runs down the drain. Why not consider harvesting the water. That's what my business is all about. Rainwater harvesting in simple terms is The collection of rainwater -- The storage of rainwater and the distribution of rainwater too where your want it.