Schedule E established water quality objectives for 12 PPWB eastward transboundary rivers. The objectives are descriptions of water quality conditions that are known to protect human and ecological health, and are acceptable to upstream and downstream provinces. PPWB member agencies have agreed to endeavour to meet these objectives. This cooperative approach will ensure that the water remains fit for both current and future uses, including use by people, aquatic life, consumers of aquatic life, and agriculture.

From Schedule E, the water quality duties of the PPWB Board are to:

• monitor the quality of the aquatic environment in the river reaches and make comparisons with the PPWB objectives;
• review the appropriateness of the PPWB objectives;
• provide written reports on the quality of water in interprovincial river reaches and on water quality issues;
• promote the establishment of compatible water quality objectives in the Prairie provinces;
• promote a preventive and proactive ecosystem approach to interprovincial water quality management; and
• promote the recognition of the interdependence of quality and quantity of water in the management of watercourses.

Over the years the PPWB has developed an active water quality program to assess whether PPWB objectives have been met. This program includes Environment Canada monitoring the water quality at 12 PPWB monitoring stations.

In recent years, the PPWB has worked towards an integrated ecosystem and watershed approaches in dealing with environmental issues. Complementing these approaches is the adoption by the federal-provincial Canadian Council of Ministers of Environment (CCME) of the source to tap, multi-barrier approach to protecting drinking water for Canadians. The multi-barrier approach highlights the importance of protecting the lakes, rivers and aquifers which are the sources of our drinking water, as well as ensuring effective treatment and distribution systems.

The PPWB supports the multi-barrier approach, and its agencies are committed to identifying, understanding and reducing the human and environmental impacts of micro-biological and chemical substances which contaminate water sources and aquatic ecosystems. All board agencies share the knowledge of the threats to water quality, strategies to reduce or eliminate the impacts and information on water quality issues and trends in ecosystem health