Canada's Great Lakes, as seen from space in the documentary Waterlife. (Mark Alberts/Mongrel Media)

If documentarian Kevin McMahon should ever decide to quit his day job, he could easily find work inspiring young minds in a classroom.

Waterlife might be a horror movie about the toxic sludge infusing the water that 35 million people drink every day, but it’s also a love story.

In conversation, McMahon’s enthusiasm and passion is infectious, and both qualities course through his new film, Waterlife, a stunning cri de coeur on behalf of Canada’s beleaguered Great Lakes. The film’s urgency set it apart from most of the other documentaries that screened at this year’s Hot Docs; festival jurors certainly agreed, awarding Waterlife a Special Jury Prize.

While Waterlife begins as what McMahon calls “a watery road trip,” it is also a plea to save the Great Lakes. The film starts with awe-inspiring, high-def footage of beluga whales in the St. Lawrence River, but by the time McMahon wends his way through all five Great Lakes — discovering invasive zebra mussels, Prozac-infested waters and damning Environment Canada reports along the way — viewers might feel more than a little shaken by all they’ve learned.

“You do want people to be terrified,” McMahon says, “and you want them to be mad, too.”

Waterlife director Kevin McMahon surveys the muddy waves of southern Lake Erie. (John Minh Tran/Mongrel Media)

The director, who received the retrospective treatment at Hot Docs 2007, has been crafting innovative docs for years, ranging from the water-themed The Falls (1991) to the masterful McLuhan’s Wake (2002). Waterlife is by turns gorgeous, thought-provoking and terrifying. One of the triumphs of the film is that it provokes a delicate balance of emotions throughout. Waterlife might be a horror movie about the toxic sludge infusing the water 35 million people drink every day, but it’s also a love story. Dazzling images of something as familiar as droplets bursting forth from a lawn sprinkler are filmed with such care that they invite a new-found appreciation for a substance we all take for granted.

“It’s what I love to do,” says McMahon when asked about Waterlife’s unique look and feel. “To me, the fun of it is to take on a complex subject and find an interesting way to do it, because very often, my films are about things that are obvious. It’s about trying to give people a different perspective on things that either are in front of their faces and they can’t see or that they know but they just haven’t really thought about.”

In Waterlife, this ambitious aim is often achieved with devices not commonly associated with documentaries. The film’s beating heart is the Great Lakes, but McMahon is a keen storyteller, and he wraps other compelling narrative strands around his subject. Using a map and beautiful CGI, McMahon follows a water molecule on its lively journey from Lake Superior all the way to the ocean. We meet with locals along the way, including a Thunder Bay resident named Josephine Mandamin, whose one-woman mission to raise awareness — by walking the perimeters of all five Great Lakes — serves as a framing device.

Josephine Mandamin, leader of the Mother Earth Waterwalk, in a scene from Waterlife. (John Minh Tran/Mongrel Media)

At one point, Josephine remarks that some people think she’s crazy for conducting this ongoing protest, but she persists – walking in speedy, determined steps, symbolic pail of water in hand. McMahon met with similarly incredulous reactions when he first pitched the idea for Waterlife six years ago: “Everybody was like, ‘Yeah, whatever, water. Who cares?’”

He credits the unexpected success of Al Gore’s eco-doc An Inconvenient Truth with finally helping to get his own project off the ground. One suspects his passion for his subject also opened doors.

This level of commitment might seem unusual for a veteran filmmaker, until McMahon explains his personal connection to the bodies of water that take centre stage in his doc. He describes his childhood home in Niagara Falls, summers spent on Lake Erie and frequent camping trips to Lake Huron with his own kids. McMahon recalls an early awareness of the toxic dangers besetting the water. “I grew up swimming in the Niagara River, and I clearly remember when the moment came when I was 10 or something, when it was like, ‘Sorry, can’t do that anymore.’”

And “Sorry, can’t do that anymore” is ultimately what Waterlife is all about. As the film progresses, it gains momentum, weaving scientific data with artful, more accessible images (like scenes with some very freaky mutant fish), until viewers are left to ponder the fate of the lakes. Scenes of showers, bottled water and everyday taps become loaded. Many viewers will likely feel compelled to take action at Waterlife’s close.

McMahon invites this response, and his advice to audiences is this: “They should demand accountability from their politicians. And luckily enough on this issue, basically, the first politician that walks in front of their face has some responsibility, because it goes all the way up the chain.”

Children play in the Crown Fountain in Chicago's Millennium Park on the Lake Michigan waterfront. (John Minh Tran/Mongrel Media)

Indeed, to hear him tell it, McMahon is much more concerned about what happens after viewers watch his ode to the near-extinct Great Lakes. “The film ends with the URL of a website [www.ourwaterlife.com] to give you that kind of easy, immediate outlet, and we’ve established relationships with a bunch of environmental groups, so that if people do want to act, in whatever way, there’ll be places where we can funnel that energy.”

Energy might seem like a strange word to attach to a subject that’s often reserved for musty high-school textbooks, but it is exactly what audiences will take away from Waterlife.

“I don’t think documentaries have to have an obvious civic agenda, but I do think that they should have a usefulness to people. Maybe it’s expanding their minds, maybe it’s making them look at something differently, but they need to do more than entertain. They need to open you up to another world, another way of looking at the world.”

Waterlife opens in Toronto on June 5, Vancouver on June 19 and throughout the summer in other Canadian cities.

Lee Ferguson writes about the arts for CBCNews.ca.