Rainwater harvesting collects rainwater from rooftops in tanks for non-potable uses like toilet flushing and gardening. It can save 30-50% of drinking water usage. A typical system filters rainwater into a buried storage tank, from which a pump distributes it through a separate piping system. Greywater recycling cleans and filters used water from baths and sinks for similar reuse, saving up to 40% of drinking water. Combining the two systems maximizes water savings.