Boise backs industrial sewer cutoff for Dairygold
City of Boise Department of Public Works, Idaho · Meeting date: November 4, 2026 · Published: November 5, 2026
The decision marks the first sewer termination pursued in Boise's pretreatment programme since it began in 1985. Dairygold said cutting its industrial discharges would force it to shut its plant, but commissioners concluded that repeated enforcement and treatment upgrades had not delivered sustained compliance.
Key points
- The commission voted unanimously to deny Dairygold's appeal, confirm staff direction and set 15 January as the termination date for its two industrial sewer outfalls.
- The termination does not cover Dairygold's domestic wastewater connection, but would halt process wastewater discharges to the West Boise Sewer District system and West Boise Water Renewal Facility.
- City staff said Dairygold had received 33 months of compliance schedules in the preceding 48 months, while administrative fines had reached Boise's $1,000-per-violation-per-day cap.
- Dairygold said it had removed phosphoric-acid cleaning chemicals, installed a second dissolved-air flotation unit and planned a rapid-mix coagulation tank, but did not provide a completed engineering compliance plan.
Full report
Boise's Public Works Commission has upheld staff's recommendation to terminate Dairygold's industrial sewer service, setting 15 January as the date for closure of the dairy processor's two industrial connections to the West Boise Sewer District collection system.
Commissioners voted unanimously to deny the company's appeal after hearing competing accounts of its pretreatment performance and proposed upgrades. The action applies only to industrial wastewater outfalls, not the domestic sewer connection at Dairygold's Boise facility.
Pretreatment programme manager Sarah Huron said the company had accumulated permit violations and reporting deficiencies from 2021 through October 2026. The city had progressively used compliance schedules, corrective-action requirements, enhanced monitoring, notices of violation and administrative orders before pursuing termination, she said.
The enforcement history began after Dairygold increased production without first expanding its pretreatment capacity, leading to an operational incident that disrupted the biological treatment process. Staff said non-compliant effluent subsequently contributed to increased solids handling, biochemical oxygen demand in plant effluent, and electricity usage at the West Boise Water Renewal Facility.
Dairygold was given an initial 15-month compliance schedule in November 2021, followed by a four-month schedule in 2022 and a 90-day schedule in 2023. It later received an 18-month schedule to meet newly adopted citywide phosphorus and ammonia limits, which ended on 15 August 2025. City staff said the company had received 33 months of compliance schedules over the preceding 48 months.
The company exceeded the 35.9mg/l phosphorus limit shortly after that final schedule expired, according to staff. In 2026, the city cited further phosphorus and ammonia violations, reporting failures, late corrective-action submissions and late fine payments. It also cited 13 days of dissolved oxygen readings below the 2.0mg/l minimum from 22 September.
Huron said the city had reached the $1,000-per-violation-per-day administrative-fine limit under Boise City Code. Sewer termination was therefore the next enforcement option under the city’s Department of Environmental Quality-approved enforcement response plan. Continued non-compliant industrial wastewater also posed a heightened risk while the West Boise Water Renewal Facility is under construction, she said.
Dairygold environmental compliance director Doug Pettinger said the company had made substantial improvements. It removed phosphoric acid from all plant cleaning processes by 8 June, installed a second dissolved-air flotation unit in September and planned to install a rapid-mix coagulation tank following engineering work expected by the end of January. He said the second DAF had cost about $300,000.
Pettinger disputed the significance of the dissolved-oxygen event, arguing that a failed probe had produced the low readings and that upstream aeration tanks and the DAF meant actual dissolved oxygen was above the limit. He also raised concerns about missed third-party sampling and discrepancies between the district's flow meter and Dairygold's meter, although staff said pretreatment enforcement calculations used Dairygold's self-reported flow data.
The dairy requested more time to demonstrate compliance. Pettinger told commissioners that termination would leave the facility unable to manage about 300,000 gallons a day of wastewater, forcing a plant shutdown and potentially affecting milk deliveries from farmers. Staff said Dairygold could evaluate options including hauling waste to facilities that accept it, but that the city could not continue accepting non-compliant wastewater.
Commissioners acknowledged Dairygold's recent investment but said the company had not provided a sufficiently detailed or time-bound compliance plan. They also stressed the need to apply the pretreatment rules consistently across industrial users and protect the city's own regulatory standing.
This summary was generated by AI based on the source document and may contain errors.
Source: Public Works Commission Regular Meeting, City of Boise Department of Public Works