Established in the late 1960s, the WWTP is located a mile east of downtown and serves City of Driggs, City of Victor and some development outside of the cities along main sewer lines.

The WWTP has been upgraded over the decades and converted from a lagoon system to a mechanical plant in 2013. The 2013 conversion to an MSABP Fixed Film Treatment Process, a Multi-stage Activated Biological Process Plant that uses bacteria to digest the contaminants in wastewater, was designed and constructed to handle 10 years of anticipated growth of up to 900,000 gallons/day. An additional 10 years of growth were included in the 2013 WWTP Plan, but not all infrastructure was installed to reduce construction and operational costs.

In 2018, staff identified groundwater infiltrating the pipes, and much work was done to reduce this unnecessary water treatment, a process called I & I Reduction: Inflow and Infiltration Reduction.

Facility expansion was delayed due to lower-than-anticipated population growth in the 2010s, so the current plant is still meeting demand for capacity. However, 2020 marked the 10-year period to reassess the capacity and growth of the community's treatment needs for the next 20 years. Forsgren Engineering conducted the study, and MurraySmith, based in Boise, Idaho, was hired for a third-party review of the Draft Facility Plan by Forsgren Engineering in 2022 to ensure that this is the most fiscally responsible plan. The review confirmed that the plan was correct.

City Council adopted the Teton Valley Regional WWTP Plan Study  on November 7, 2023, setting the stage for a plant expansion and upgrade that will come online in late 2028. Please read the What steps are being taken to fix the problem? section below for the projected timeline.

Yes. The WWTP is a Multi-Stage Activated Biological Process (MSABP) plant, which uses bacteria to digest the contaminants in wastewater. The MSABP has been unable to remove ammonia constantly, and the facility has long been out of compliance by exceeding the ammonia limits of its water discharge permit. Treated effluent is discharged into the unnamed tributary of Woods Creek which then flows approximately 3 river miles to reach the Teton River. In addition to the ammonia issue, the current facility is fast approaching its hydraulic and biological capacity and needs to be expanded.

There are different classifications of treatment plant capacity. The current plant has a daily hydraulic capacity of 0.9 million gallons of liquid and a peak hour capacity of 2.0 million gallons per day.  Based on current flows and growth, the current facility will exceed the daily capacity in 2033 and the peak hour capacity in 2029.

Loading Capacity, which is how dirty the water is with things like human waste, ammonia, grease, etc., is broken down into subcategories. Levels measured in this category are the BOD or biological oxygen demand, the TSS or total suspended solids, Ammonia, and E. Coli. The current facility is designed to process 1,877 lbs of BOD/day; last year averaged 1,625 lbs of BOD/day (87% of capacity). The plant is removing 90-95% of BOD and TSS; thus, it does not exceed discharge limits in these categories.

However, it is approaching the designed loading capacity and has historically failed to meet standards to mitigate the ammonia levels. Therefore, the city is in the process of a Facility Expansion and Process Upgrade to comply with state, federal, and Clean Water Act regulations.

The city initiated the design of an expanded and upgraded facility to process wastewater through 2048, assuming an annual growth rate of 4%.

1. 2018-2023: A new 20-year Facility Plan was created by Forsgren Associates, approved by the State of Idaho, and adopted by the City Council.  
2.  April 2024: Forsgren Associates began the design of the facility expansion and upgrade to an extended, aeration-activated sludge facility.  A Membrane Bioreactor System was selected as the preferred technology due to its performance, timing, and ability to fit into existing infrastructure.
3. November 2024: Kubota Membrane USA was selected to provide membrane bioreactor equipment.
4. December 2024:  A 30% Design and Cost Estimate was presented to the City Council, with an estimated cost of $31.6 Million.
5. August 2026:  Forsgren Associates presented an updated 60% Design and Cost Estimate to the City Council, with inclusion of the Victor service area. The estimated cost was $30.3 million, but the City is using $35 million as a working number to account for inflation, and additional costs for lagoon decommissioning and a possible upgrade to meet the Class A water re-use standard.
6. September 2026: The City submitted the Preliminary Engineering Report to the State of Idaho for review and approval.
7. February 2027: Forsgren Associates will present a 90% Design and Cost Estimate to the City.
8. July 2027: Submit 100% to the State of Idaho for review and approval.
9. December 2027: The City of Driggs will issue the notice to proceed to the construction contractor.
10. April 2028: Begin construction of facility expansion and upgrade.
11. December 2030: Initial start-up of the expanded and upgraded WWTP Facility.
12. December 2030: The expanded and upgraded plant will be fully online.
13. February-September 2030: Removal of accumulated sludge from lagoons.

Yes, a significant amount of the existing equipment, along with the existing buildings and piping, is being re-used.  The membrane bioreactor technology was selected as it will fit into our existing concrete basins and not require additional construction of new concrete basins.

However, some new construction is required, including a building over the existing concrete basins that will house new air blower units and bio-solids handling equipment.

The primary component of the project funding package includes a $25 million Idaho DEQ loan with partial ($6.34 million) principal forgiveness, and an interest rate of 2-3% over 20-30 years. Additional DEQ loan funds, to account for the Victor service area being re-added to the plan/design, are being discussed with DEQ. The City expects to finalize the loan details in 2027. Repayment of the loan, authorized through a judicial confirmation, will be funded partly by new connection fees, customer rates and the City's local option sales tax.

The impact to customer rates will depend on the final loan details and how the repayment is balanced between different funding sources. A customer survey in the fall of 2026 will help the City appropriately allocate the repayment costs.

Yes, all users connected or connecting to the facility will be required to pay their fair share of the upgrade costs.  Connection fees will be adjusted to ensure new development is paying for their associated capacity expansion.

Yes!

Disconnect roof/storm drains from your sewer, and don’t connect sump pumps to the sewer.

DO NOT FLUSH wipes, feminine products, or grease! Using water conservation best practices and minimizing difficult-to-process waste will help our current situation. See our Water Conservation and FOG prevention information on the Utilities: Water and Sewer Page

Please contact city staff with any additional questions that we can help answer. As more information becomes available with the new facility plan and phases toward a solution, we will update this page. Thank you for taking the time to learn about our city's wastewater treatment plant.

• July 7, 2026 Driggs Invitation for Joint Council Worksession
• July 29, 2026 Joint Worksession 1: Agenda | Minutes
• September 16, 2026 Joint Worksession 2: Agenda

• 3/5/2026 Filed Complaint and Demand for Jury Trial
• 7/7/2026 Order of Dismissal

USA vs City of Driggs Consent Decree

2025 Quarter 2 Report

2025 Quarter 3 Report

2025 Quarter 4 Report

2025 Annual Report

2026 Quarter 1 Report

2026 Quarter 2 Report

2026 Quarter 3 Report

2026 Quarter 4 Report

Environmental Protection Agency Press Release by the EPA on January 16, 2025

Expansion and Major Upgrades to Teton Valley Regional Water Reclamation Facility: EPA Agreement Sets Path for Environmental Improvements and Sustainable Growth by City of Driggs January 15, 2025. Read the full Consent Decree online , the Amended Complaint , the Complaint Appendix A , and the Notice of Lodging . A public comment period is open 01/22/2025 - 02/21/2025. Anyone interested in commenting can find more information on the justice.gov website for this case .

Rising Temperatures in the Spring Cause Normal and Temporary Odor from the WWTP by City of Driggs May 8, 2023.

Driggs' officials swamped with attention, concern over wastewater lawsuit by Conner Shea October 31, 2022

Driggs' temper running thin with wastewater facility by Conner Shea October 19, 2022

Letter From the Mayor: October 10, 2022

Driggs approves utility fee increase By Julia Tellman Sep 28, 2022

Driggs Waste Water Treatment Plant Odor is Temporary By City of Driggs Jun 13, 2022

Driggs tests new sewage plant cleaning process By Julia Tellman Apr 28, 2021

Sewage plant upgrades are needed to achieve discharge compliance, study says By Julia Tellman Mar 10, 2021

Driggs faced with wastewater plant decision by Julia Tellman Feb 12, 2020