Rainwater that is collected from the roofs of buildings and other (e.g., at-grade) impervious surfaces and does not leave the land parcel where it was collected and has not entered an off-site storm drain system or channel, a flood control channel, or any other stream channel.

A system that collects stormwater runoff for purposes of storage, infiltration, irrigation, or other applications, and/or to address regulatory requirements to manage stormwater quality and quantity; also called stormwater harvesting system or stormwater capture system.