Helping Protect Water Quality for BC’s Largest Water Provider  

Since 2015, HDR has assisted Metro Vancouver with system assessments and recommendations as part of the utility’s drinking water system corrosion control program. Initially, we were hired to revisit corrosion control analyses and recommendations that one of our predecessor companies had prepared from 1988-1992. The purpose was to establish the ideal pH and alkalinity levels to minimize metal release into treated water through Metro Vancouver’s transmission system, its downstream municipalities’ distribution systems and through customer premise plumbing in British Columbia’s Lower Mainland.

Our analysis included reviewing the 1,800-million-liters-per-day Seymour-Capilano Filter Plant's lime and carbon dioxide feed systems and the 380-MLD Coquitlam Water Treatment Plant's soda ash system. Based on the study’s results, we recommended increasing the treated water pH, adjusting the two plants from 7.7 to 8.3-8.5 and increasing the alkalinity from 8-20 milligrams per liter as calcium carbonate (CaCO3).  

Over the following decade, we assisted Metro Vancouver to periodically assess system health and to help determine if a minor pH adjustment would provide additional protection. Data has shown a beneficial reduction in metal corrosion throughout the 2.8-million-person service area.