C.R.S. § 35-11-107

(1) An irrigation system utilizing chemigation on and after January 1, 1990, or an irrigation system which has been issued a provisional chemigation permit shall have, as component parts thereof, a properly installed and functioning: (a) Backflow prevention check valve and vacuum relief valve between the main check valve and the irrigation pump; (b) Inspection port to check the performance of the check valve on the irrigation pipeline; (c) Automatic low-pressure drain placed between the main check valve and the irrigation pump so that a chemical will drain away from the source of water supply; (d) Check valve in the chemical injection line; and (e) Simultaneous interlock device between the power system of the chemical injection unit and the irrigation pumping plant to protect the water supply from contamination in the event such pumping plant ceases to operate. (2) An irrigation system which would otherwise be subject to all of the requirements of subsection (1) of this section may be exempted from one or more of such requirements if the owner of such irrigation system can demonstrate that the possibility of the source of water from which the irrigation system draws its water cannot be polluted or contaminated as the result of utilizing such irrigation system for chemigation.