Water Quality | Draft Environmental Assessment for Eagles Grove | Public Hearing September 29, 2026 | Comment Period Ends October 17, 2026

The Proposed Action is for the Montana DEQ to issue public water supply and wastewater plan approvals for Eagles Grove, a 15.43-acre parcel located at 1630 Targhee Pass Highway (Highway 20), in the southwest quarter of Section 21, Township 13 South, Range 4 East, Gallatin County, Montana (see Figure 1). The East Fork of Denny Creek runs along the eastern side of the property (see Figure 2, Figure C-2 and Figure 3). The sanitary facilities include: (1) a new public water supply well (GWIC ID 339231), constructed September 23, 2025, with chlorine disinfection, finished water storage, booster station, water mains, and service connections, designed in accordance with Circular DEQ-3; (2) a new sewage collection and onsite treatment system meeting Circulars DEQ-2 and DEQ-4, consisting of 6-inch PVC gravity sewer mains, 48-inch precast manholes, a 15,000-gallon septic tank, a 5,000-gallon surge tank, and a SepticNET Level 2 advanced treatment system reducing effluent nitrogen to 7.5 mg/L; and (3) a pressure-dose subsurface absorption area with four zones, sized at 0.4 gpd/sf for the primary drainfield and 0.2 gpd/sf for the replacement drainfield.

 The Proposed Action would serve 56 short-term, single-bedroom rental cabins akin to hotel rooms, requiring no full-time staff on property. Flow calculations conservatively assume two employees (property management/cleaning) and estimate wastewater flows of approximately 5,000 gallons per day, with total daily occupancy assumed at 126. The facilities would operate year-round. The existing public water supply well (GWIC ID: 219958, PWSID #MT0004318) formerly served commercial uses on the property but is no longer active or permitted; a third well of unknown GWIC ID would be abandoned.

Associated Materials:

• Draft Environmental Assessment – Eagles Grove
• Attachment A - Figures
• Attachment B – NRCS Soil Report
• Attachment C – Nondegredation Report
  • Appendix C1 – Nondegredation Report – Final
  • Nondegredation Submittal Appendices
• Attachment D – Wetland Delineation Report
• Attachment E – Wildlife Reports
• Attachment F – Cultural Resources

Public Comment Period Ends: Comments must be received or postmarked by 11:59 p.m. October 17, 2026

Send/Submit Comments to:

DEQ
Engineering Bureau
P.O. Box 200901
Helena, MT 59620-0901

Or electronically to:  DEQEngProgramMEPA@mt.gov

Public Hearing:

DEQ will hold a public hearing for the Eagles Grove, Tuesday, September 29, 2026, at 5:00 – 7:00 p.m. virtually via Zoom. See the Zoom meeting information below.

Via Zoom:

Please click the link below to join the webinar:
https://mt-gov.zoom.us/j/81710465335?pwd=sASrf86nuPVSf8lxOjhPduErI9K7Or.1

Join via audio: 

Webinar ID: 817 1046 5335

Passcode: 060870

Or Telephone: +1 206 337 9723 US (Seattle)

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Tags: MEPA, Public Comment, Water and Public Meeting