I have also seen this, it is for a simple reason, every major city on the US east coast, has its water supply reservoir. Many of these cities are approaching the max amount of water that can be consistently withdrawn from that reservoir under current conditions. Those cities are generally taking two approaches to the problem of increasing demand, either change conditions of the reservoir by changing the forest to one that has greater runoff, or reducing looses in transit to customers. The cover type conversions can increase runoff by up to 10%. The losses in the distribution system are slowly being dealt with, as most of the cities have hundreds of miles of pipe that in some places is over 100 years old.
There are two other options that cities have, try to persuade citizens to use less water, what you complained about. The other option is to build new reservoirs, which would be a political fight of epic proportions because this would be unlikely to make them popular with the neighbors (eminent domain seizers of land, Environmental impact statements, etc.)
Thus several cities actually are taking a closer look at desalinization, as a new source of water. The Author of the article did not say where in the US water from Canada was to be sent.
I spent a week on Malta (which is a delightful place and a great off-beat vacation spot), and they have several desalinizing plants to provide water. Israel just built a big plant and the cost per gallon of the water it produces is less than I am paying for well water from a cooperative water utility.