Backflow prevention in the chemical line.

7-10-02-05. Backflow prevention in the chemical line. A spring loaded, chemically resistant check valve having a minimum opening pressure of ten pounds per square inch [69 kilopascals] must be located at the injection port of the irrigation system. History: Effective October 1, 1988. General Authority: NDCC 4.1-35-03 Law Implemented: NDCC 4.1-35-02, 4.1-35-03