Under National Pollutant Discharge Elimination System permit number CO0034665, Oldcastle SW Group, Inc., d/b/a Four Corners Materials, is authorized to discharge from its wastewater treatment facility located in the NW 1/4 of Section 14U, Township 34 N, Range 7 W, latitude 37.191371° N and longitude 107.586513° W, La Plata County, Colorado, to the Los Pinos River in accordance with discharge point(s), effluent limitations, monitoring requirements and other conditions set forth herein. Authorization for discharge is limited to those outfalls specifically listed in the permit.

This permit was issued on July 1, 2019 and modified on April 1, 2020.

• CO0034665 Four Corners Materials Modified Final Permit (PDF)(25 pp, 533 K, April 1, 2020)
• CO0034665 Four Corners Materials Statement of Basis for Final Permit (PDF)(12 pp, 601 K)
• CO0034665 Four Corners Materials Statement of Basis Addendum for Final Permit (PDF)(9 pp, 262 K, April 1, 2020)