Although Ontario may never drain all its vast water resources, there are still significant dangers. Local shortages have occurred, especially in areas that rely upon groundwater. Water takings may have long term negative impacts on local ecosystems, even if the taking is relatively small in comparison to the body of water from which it is being withdrawn. Water shortages have resulted in water being shipped or piped over great distances, using valuable energy and resources in the process. Perhaps more significantly, there have been numerous proposals to transfer large quantities of Ontario's water to other thirsty jurisdictions.
Most proposals involve massive diversion projects either by canal or long range transport.
These proposals provide a further potential threat to Ontario's water supply in that, once initiated, they may be difficult to halt, and that the quantities of water involved may have a significant impact upon water supplies. Requests to utilize water are analyzed individually, rarely in relation to that of other users. There is no societal statement as to what uses of water are to be given priority in Ontario. More importantly, it is not publicly recognized that the ecosystem function of water must be given precedence over other uses. Problems thus occur because the cumulative impact of various water uses are not considered, leading to competition for the same water supplies.