The Oro Valley Stormwater Utility Commission on Jan. 16 reviewed results of a Nov. 14, 2024 compliance audit by the Arizona Department of Environmental Quality and a Q2 report on the town’s municipal separate storm sewer system (MS4). Dennis Roberts, interim stormwater utility manager, summarized the audit and the MS4 program's status and said the town had addressed minor deficiencies identified during the inspection.

The audit team conducted on-site visits to four locations in Oro Valley, including an active construction site, a completed subdivision site, municipal facilities and an MS4 outfall near the water utility site on N. Push Ridgeview Way. Roberts said the audit’s observations were “primarily associated with enforcement response plan for the town’s illicit discharge detection elimination system, suggestions for annual training on illicit discharge detection and elimination, and good housekeeping,” and added the town corrected issues promptly after the exit debrief.

Why it matters: Compliance with the Arizona Pollutant Discharge Elimination System permit and ADEQ oversight governs the town’s ability to monitor stormwater discharges, maintain sampling and training routines, and avoid enforcement actions. Commissioners said they want assurance the town’s approach fits the region’s arid hydrology.

Roberts told commissioners the training deficiency cited by ADEQ stemmed from a missing sign-in sheet: “we are being required to redo the training and get the signatures from the employees.” He said the town also corrected minor maintenance items observed by inspectors and will submit a comment-response letter with photos to ADEQ this week.

Commissioners raised technical and programmatic questions. Commissioner Richard asked whether EPA-driven sampling requirements are suited to ephemeral, arid washes in the West and whether state agencies have discussed adapting protocols for areas with infrequent flows. Roberts noted staff must often wait for significant rains to sample and said, “we do continue to submit our samples and get positive feedback from the agencies in our process here.”

Commissioners requested a future agenda item for staff to present the town’s sampling procedures, equipment availability and how staff coordinates sampling after rain events. Roberts agreed to prepare a staff report and said he would reach out to EPA contacts for feedback before presenting to the commission.

The commission did not take formal action on the audit or the MS4 report at the meeting; members noted ADEQ inspectors offered positive feedback while identifying items to correct.

Looking ahead: Staff will return to a future meeting with a presentation on sampling procedures and the town's approach to meeting ADEQ/EPA sampling requirements in an arid environment.