Friday, September 28, 2018 - 10:45 AM

Data Available on Manganese Levels in Water Supply

Petty Harbour Long Pond Water Treatment Facility

The levels of manganese being monitored throughout the Petty Harbour Long Pond (PHLP) Water Supply distribution system continue to decrease. Changes in the treatment process have made a positive difference in the levels of manganese. Water continues to be monitored daily, and the City reminds residents serviced by PHLP that clear water is safe to drink.

Manganese Measured on September 27 mg/L
PHLP raw water 0.045
PHLP treated water at plant 0.008
Average of three samples in PHLP distribution system 0.009

In addition to monitoring water samples going in to and coming from the PHLP treatment plant, the City tests for manganese from 14 sampling ports located throughout the PHLP distribution system. The manganese data collected from June to September 2018 is available here and is also represented in a graph.

Of the 221 water samples taken from various points in the PHLP distribution system, seven were recorded above Health Canada’s proposed maximum allowable concentration of 0.12 mg/L. Of the seven that were showing above acceptable levels (ranging 0.13 to 0.21 mg/L) all were attributable to a local disturbance in the area such as a water main break, or water main maintenance.

Manganese mg/L
Health Canada Proposed maximum allowable concentration 0.12
Highest Level Recorded in PHLP distribution system 0.21
Average of 221 samples in PHLP distribution system 0.037

The provision of safe and quality water to residents is a top priority for the City of St. John’s. The City reports to the provincial government who independently sample and test the City’s water four times per year. Since 2016, the samples recorded from PHLP have received an ‘excellent’ ranking by the Department of Environment and Conservation’s Drinking Water Quality Index.

The drinking water station at the City’s Depot at 25 Blackler Avenue will remain open as a precaution, the others are now closed. Water continues to be monitored daily, and the City reminds residents serviced by PHLP that clear water is safe to drink, and any issues should be reported to the City.

Updates will be provided if the situation changes. All details on the Manganese issue are found on the City’s website.