Colorado · ECMC Rule 615
Colorado’s groundwater baseline rule, ECMC Rule 615 (2 CCR 404-1-615), sets the most detailed sampling program of the four states DIG serves, and it continues for the life of the well. DIG runs the Rule 615 water chemistry and dissolved-gas analyses, the isotope follow-up when the trigger is met, and delivers results in the electronic data deliverable format the Director accepts.
NELAP/TNI and ISO/IEC 17025:2017 accredited · A2LA certificate 7797.01 · nonpotable water
Before 2021, statewide groundwater baseline sampling in Colorado fell under COGCC Rule 609. ECMC Rule 615 now sets a single statewide requirement for wells with permits submitted or pending on or after January 15, 2021. Wells approved earlier follow the sampling protocols in their original permits.
What Rule 615 requires
| Requirement | Rule 615 |
|---|---|
| Applies to | Wells with a Form 2 or Form 4 Notice to Recomplete submitted or pending on or after January 15, 2021 |
| Water sources | All available water sources, up to 4, within a ½-mile radius of the proposed well |
| Initial baseline | Within 12 months before setting conductor pipe |
| First follow-up | 6 to 12 months after completion |
| Second follow-up | 60 to 72 months after completion |
| Ongoing | Every 5 years (57 to 63 month interval) for the life of the well |
| Post-abandonment | 6 to 12 months after the well is plugged and abandoned |
| Isotope trigger | Free or dissolved methane, ethane, or propane above 1.0 mg/L requires gas compositional and stable isotope analysis |
| Immediate notice (Form 42) | Thermogenic or mixed gas; methane increase above 5.0 mg/L between sampling periods; methane at or above 10 mg/L; BTEX or TPH detected |
| Data submission | Results to the Director in an approved electronic data deliverable format, with a PDF lab report, via Form 43 |
Rule 615 analytes and how DIG covers them
| Rule 615 analyte | DIG |
|---|---|
| pH, specific conductance, TDS | Yes |
| Alkalinity | Yes |
| Major anions and cations | Yes |
| Barium, boron, selenium, strontium | Yes (metals by 6010D) |
| Dissolved gases: methane, ethane, propane | Yes (RSK-175) |
| Gas composition and stable isotopes (above 1.0 mg/L) | Yes, on the same chain of custody |
| TPH and BTEX | Yes (GRO/DRO and BTEX by 8015C) |
| Bacteria (iron related, sulfate reducing, slime forming) | Available upon request by BART (Biological Activity Reaction Test), run in-house (not within A2LA scope); may increase standard and rush turnaround times. |
Your Rule 615 deliverable
- Analytical report (PDF)
- ECMC electronic data deliverable, ready for your Form 43 submittal
- Interpretive plots in Excel
- Interpretation of isotope results by a DIG geochemist on request
When the 1.0 mg/L trigger is crossed
Colorado’s isotope trigger is the lowest of the four states. When dissolved gas exceeds 1.0 mg/L, the rule calls for compositional and stable isotope analysis to tell thermogenic gas from biogenic gas. DIG runs both on the same sample. Our geochemists can explain what the result means before you file Form 42.
Sources
- ECMC Rules, 600 Series: Safety and Facility Operations Regulations (Rule 615, Groundwater Baseline Sampling and Monitoring; PDF)
Ready to sample in Colorado?
Request kits and a quote, or download the chain-of-custody form. A qualified scientist can review your sampling plan before you go to the field.
