5 Colo. Code Regs. § 1002-62.18
The provisions of sections 25-8-202 and 25-8-501, C.R.S., provide the specific statutory authority for adoption of the attached regulatory amendments. The Commission also adopted, in compliance with section 24-4-103(4) C.R.S., the following statement of basis and purpose.
BASIS AND PURPOSE
The Commission made several editorial revisions to Regulation #62 to provide clarity and/or update terminology. Those changes that are more noteworthy will be identified in the discussion for the section where they were first made.
The Commission added a new applicability section (62.2) to clarify the Commission's intent, consistent with past Division practice, that the effluent limitations and other conditions of Regulation #62 are to be incorporated into discharge permits issued pursuant to Regulation #61 and that they are not self-implementing.
The Commission revised the language in section 62.3 to clarify that the applicable limit must be met prior to discharge to state waters. This is particularly important for discharges to ground water in order to ensure that the technology-based treatment requirement has been met and will typically require that compliance with the limits be demonstrated prior to application to the land. The Commission also revised the wording of this section and the remainder of the regulation to delete "wastewater" and, generally, replace that term with "pollutant(s)" in order to be consistent with the language of the Colorado Water Quality Control Act.
The Commission deleted the allowance in section 62.3 (renumbered to 62.4(2)) for a compliance schedule to meet the identified limits as:
The Commission modified the newly-numbered section 62.5 (previously 62.4) to provide that the numeric limits in that section will only be applied when the Division determines that a pollutant is "of concern" for that particular discharge. The Commission also modified section 62.4 to add flexibility for the Division to require implementation of best management practices (BMPs) in lieu of numeric limitations where it finds the application of numeric limits to be infeasible. The Commission expects that this provision would be particularly applicable to situations where the activities will discharge such minor amounts of pollutants that an in-stream water quality standard will not be exceeded or where sampling of the discharge, such as for water line breaks and ISDS (onsite) systems, is infeasible. This language was based on a similar provision in Regulation #61 at 61.8(3)(r) and the Commission finds it appropriate to provide the same level of flexibility to the Division in imposing the technology-based requirements of this regulation to sources not subject to federal secondary treatment requirements. Finally, the Commission moved former section 62.5 to section 62.4 as it is directly relevant to the limits identified in the following section 62.4(1).
The Commission modified footnote 6 (now footnote 5) of section 62.4 to expand the exemption from the limit for total residual chlorine to discharges to ground water. Similar to the basis for the exemption for discharges to irrigation ditches, this is appropriate as there is no aquatic life use assigned to ground water. The Commission deleted the section regarding the setting of limitations for fecal coliform as limits for bacteriological indicator organisms (E. coli at present) are established in accordance with section 61.3 of the discharge permit regulations and section 31.14 of the basic standards.
The Commission modified section 61.4 to provide that onsite treatment systems are not required to collect samples of their effluent as it is generally impractical to collect samples from the bottom of a leach field. This condition will work in tandem with the modifications to section 62.4 allowing for the implementation of BMPs in lieu of requiring numeric limits.
The Commission deleted section 62.5 (Technical Data), as Regulation #61 (61.8(4)(j)) requires monitoring of discharges in accordance with EPA approved methods rather than the methods identified in this section. As was previously noted, section 62.5 was moved to section 62.4 . The Commission also found that the "Technical Data" heading for section 62.5 does not accurately describe the remaining items in that section and deleted the heading and added the remaining items to section 62.4.
PARTIES TO THE RULEMAKING HEARING
5 CCR 1002-62.18