What are the primary sources of rainwater collection for irrigation?

The primary sources of rainwater collection for irrigation are rooftops, parking lots, and other impervious surfaces. Rooftop collection is the most common method, as it provides a large surface area for rainwater collection. Parking lots and other impervious surfaces can also be used, especially in areas with high rainfall intensity. The collected rainwater is then stored in tanks or ponds for later use in irrigation.