OHA Drinking Water Services
OHA Drinking Water Services
Contact Report Details
PWS ID: OR41 90872
PWS Name: NORTHWEST ALUMINUM COMPANY
 
Who Was Contacted: Caitlin Bryan
Contact Phone: 503-680-9821 (Email address hidden)
Contact Date: 02/06/2020
Contacted By: BAILEY, NICOLE (WASCO COUNTY)
Contact Method/Location: Field
 
Assistance Type: OTHER REGULATORY - Mailed out monitoring requirements for new disinfection
Reasons: Disinfection Byproducts
Chlorine
Operations
 
Details: Dear Ms. Bryan:
This letter is to inform the Northwest Aluminum Company of the monitoring and reporting requirements for chlorine residual disinfection. The water system was to implement treatment to maintain a disinfectant residual in the distribution system by January 31, 2020 pursuant to Oregon Administrative Rules 333-061-0032(6)(g) because multiple coliform investigations were triggered within a two year period. The monitoring and reporting summarized below will take effect on February 1, 2020.
-Measure and record free chlorine in the distribution system at least twice weekly and maintain information in a logbook kept on site. An example chlorine log sheet is enclosed.
-Measure and report free chlorine with monthly coliform samples.
-Collect a raw water source sample yearly from each well in use. Samples should be labelled ‘AS’ for source water assessment with each well identified for instance as SRC-AA for Well #1 and SRC-AB for Well #3.
-Collect two (2) dual sample sets of disinfection by-products (DBPs) at appropriate sites as part of an Initial Distribution System Evaluation. Sampling will occur in August of 2020. The results will determine future monitoring. Instructions for selecting sites is enclosed.
-Collect two 6-month rounds of lead and copper tap samples at five (5) sites to evaluate water corrosivity. Sampling will occur in 2020 with the first round between January and June, and the second round between July and December. Please review the enclosed handout to ensure existing sampling sites meet the required criteria.