Kevin Freedman says for the entire month of March he's using only those 6.6 daily gallons for cooking, drinking, cleaning and sanitation, Inter Press Service reported Tuesday.
"People in Canada and the U.S. have no idea how much water they use or how much they waste," Freedman told IPS.
The average daily water use in North American is around 80 gallons, IPS reported.
"Although people live on less, it is very difficult to use just 25 liters (6.6 gallons) a day. You can't shower or use a washing machine," he said. "I'm hoping to raise awareness that water is a finite resource."
Nearly a billion people don't have good access to safe fresh water, experts say, and that number could double in one generation as growing demand for water exceeds available and sustainable supply by 40 percent.
A recent study found "peak water" has already come and gone, as humanity uses more water than can be sustained, drawing on non-renewable reserves of water accumulated over thousands of years in deep aquifers.
"Water cannot be created, it can only by managed," Margaret Catley-Carlson, a director at the Canadian Water Network, said.
"Governments see their role as delivering water to the public and industry," she said. "This has to change to sustainably managing water resources for society and the natural environment."
U.N. Secretary-General Ban Ki-moon urged governments Tuesday to make investments in water and sanitation, particularly in urban areas where the need is acute and has grown by 20 percent in the last decade. This is "a crisis of governance, weak policies and poor management, rather than one of scarcity," Ban said in a statement.