(1) The division shall develop, and recommend to the commission for adoption, rules setting forth minimum standards for the location, design, construction, performance, installation, alteration, and use of on-site wastewater treatment systems within Colorado. The commission may establish criteria for issuing variances in the rules.

(2) Every local board of health in the state shall develop and adopt detailed rules for on-site wastewater treatment systems within its area of jurisdiction. The rules must comply with the rules adopted by the commission pursuant to subsection (1) of this section and with sections 25-10-105 and 25-10-106. Before finally adopting such rules or any amendment to the rules, the local board of health shall hold a public hearing on the proposed rules or amendments. The local board of health shall give notice of the time and place of the hearing at least once, at least twenty days before the hearing, in a newspaper of general circulation within its area of jurisdiction. After the public hearing and before final adoption, the local board of health may make changes or revisions to the proposed rules or amendments, and no further public hearing is required regarding the changes or revisions. All rules and amendments must be transmitted to the department no later than five days after final adoption and become effective forty-five days after final adoption unless the department notifies the local board of health before the forty-fifth day that the rules or amendments are not in compliance with this section or section 25-10-105 or 25-10-106.

(3) If a local board of health has not adopted rules in compliance with this section and submitted them to the commission, the commission shall promulgate rules for the areas of the state for which no complying rules have been adopted, except for areas serviced exclusively by a sewage treatment works. Rules for such areas of the state promulgated by the commission must comply with the rules adopted under subsection (1) of this section and sections 25-10-105 and 25-10-106. The rules must be the same for all the areas of the state for which the commission promulgates such rules, except as may be appropriate to provide for differing geologic conditions.

(4) A local board of health may adopt rules after action by the commission under subsection (3) of this section, if the rules comply with the procedural requirements of subsection (2) of this section and are no less stringent than those promulgated by the commission. Rules of the local board so adopted become effective only after they are transmitted to the division and the division determines that they comply with this section and sections 25-10-105 and 25-10-106.

(5) In promulgating rules under this article, the commission and local boards of health shall give consideration to the protection of public health and water quality.