The safety of the drinking water we provide to our customers is a primary concern for us. Ensuring drinking water safety starts with the source water from the North Saskatchewan River and extends to the treatment plants, the distribution system and our monitoring programs. The Source Water Protection Plan (SWPP) helps to mitigate potential risks to our water supply by understanding the pressures on our watershed. These source risks are reviewed yearly as part of the Drinking Water Safety Plan review.
In our treatment plants, we use both conventional and direct filtration treatment methods. In the fall and winter months the raw water quality is fairly good and allows our plants to shift to direct filtration. This change in treatment methods requires less alum and results in significant reduction in the amount of waste that is discharged to the North Saskatchewan River. The treatment processes remove any bacteria or viruses that might be present in the untreated river water. Along with disinfection, these processes provide clean and safe drinking water for Edmonton and the capital region.
To ensure continued safety of the drinking water, we maintain adequate supply pressure in the distribution system and to all customers. This prevents contaminants from entering the system and reducing the safety or quality of the treated water. We have several ongoing maintenance programs that safeguard the distribution system; you can learn more about these programs in the Industry Leadership section of this report.
We monitor water through all treatment and distribution phases, from raw water testing to testing of treated water at the tap. These monitoring programs ensure that water in the system and consumed by our customers is safe. Along with on-line analyzers that continuously monitor critical treatment performance and water quality variables in the treatment plants, our operators perform nearly 70,000 tests on the water every year. In 2017, the EPCOR Water Laboratory carried out approximately 123,000 tests on 8,100 samples of raw water that entered the Rossdale and E. L. Smith Water Treatment Plants, partially treated water, treated water that entered the distribution system, water from the field reservoirs and from various points within the distribution system.