OHA Drinking Water Services
OHA Drinking Water Services
Contact Report Details

PWS ID: OR41 00544
Who Was Contacted: Allen Dahlberg
Contact Phone: 971-666-8512 (Email address hidden)
Contact Date: 05/11/2022
Contact Method/Location: Email
Reasons: Coliform
Details: DWS was notified that the City of Mount Angel had two total coliform detections at 855 Reagan and 400 Alder, both are E. coli negative. City followed up with repeat samples (upstream, downstream and original sites) for both positive detections. Triggered well samples for Well 6 and Well 7 are negative for negative for both total coliform and E. coli. 3 repeat samples came back positive for total coliform at 855 Reagan, 495 Alder and 290 Alder sampling sites. Operator is out of the office Friday, May 13th and DWS will follow up with the operator on Monday to complete the Level 2 Investigation form.

6/2/2022: Completed Level 2 investigation with water system and staff. Identified the following potential causes of the past multiple coliform detections: heavy hydrant use during a firefighting event, issues at the Reagan coliform sampling site, coliform sampling during rain/wind event, recent storage tank cleaning, and water stagnation in unbaffled storage reservoirs.

Corrective actions identified from the investigations:
- Take out sampling sites with known issues (Reagan) and find alternative sites. Ensure that coliform sampling is conducted as weather permits. Completed June 2022.

- Water can short circuit through the tank resulting in stagnant water. Move water through the tanks at a regular frequency (quarterly, or at a higher frequency) to prevent water stagnation. Other options can include installing storage tank mixers, installing a riser pipe inside the tank to add distance between the inlet/outlet or adding a diffuser may help move the water. The circuit rider may have other options to consider. System is scheduled to work with Heath Coakely from OAWU on June 13, 2022.

Completed June 13th: operator is hopeful doing a scheduled overflow of the tanks cleared out sedimentation. Will be conducted quarterly.

- Prevent sedimentation in storage tanks, and consider inspecting and cleaning the reservoirs at a higher frequency. Completed January 2022.
Associated Alerts: COLI22113 - 05/13/2022 - COLIFORM (TCR)

COLI22105 - 05/11/2022 - COLIFORM (TCR)

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