C.R.S. § 37-91-106

(1)(Deleted by amendment, L. 2003, p. 1678, § 6, effective May 14, 2003.)(2) A license shall not be required of any person who performs labor or services if he is directly employed by, or under the supervision of, a licensed well construction contractor or pump installation contractor. (3) Private drillers and private pump installers are exempt from all license requirements under this article; except that such entities shall be required to comply with minimum construction standards as required by section 37-91-110 and the rules of the board. (4) A license shall not be required of a professional engineer, professional geologist, or professional hydrologist or anyone directly employed by, or under the supervision of, a professional engineer, professional geologist, or professional hydrologist for the purpose of sampling, measuring, or test-pumping for scientific, engineering, or regulatory purposes. The board may promulgate rules governing such sampling, measuring, or test-pumping, and all such sampling, measuring, or test-pumping shall be done in compliance with such rules.