C.R.S. § 37-96.5-103: Small-capacity rooftop precipitation collection permitted.

(1) Precipitation from a rooftop may be collected if:

(a) No more than two rain barrels with a combined storage capacity of one hundred ten gallons or less are utilized;

(b) Precipitation is collected from the rooftop of a building that is used primarily as a single-family residence or a multi-family residence with four or fewer units;

(c) The collected precipitation is used for outdoor purposes including irrigation of lawns and gardens; and

(d) The collected precipitation is used on the residential property on which the precipitation is collected.

(2) A person shall not use precipitation collected under this article for drinking water or indoor household purposes.

(3) The state engineer may curtail rain barrel usage pursuant to section 37-92-502 (2)(a).