Wakefield, Que., residents are worried that highway expansion in the area will contaminate a popular source of drinking water.

Plans to widen Highway 5 to four lanes near the quaint Quebec village north of Ottawa could contaminate the aquifer that they have used for decades as a source of drinking water.

That fear has been backed by federal officials as well. Transport Canada performed a preliminary assessment and determined that the project — which would involve lopping off a nearby hilltop — could contaminate the aquifer.

"It's delicious, clean, clear water, and it's much higher quality than the water that we get out of our taps, so it's really, really important," said Laurie Gough, a member of a group calling themselves Save Our Spring. "It's horrifying to think that it may be destroyed with the coming of this mega-highway."

The Wakefield spring sits between the village centre and Highway 105.

SOS wants a new and more comprehensive environmental report carried out and more consultation before there is any more work done to extend the highway beyond Wakefield. They have also started a letter-writing campaign aimed at key local, provincial and federal officials.

But so far, neither Transport Canada nor Quebec's Transportation Ministry is willing to open up the plan to consultation.

Work on a 2.5-kilometre portion of the highway began in 2010. Phase 2, which extends 6.5 kilometres from Meech Creek to Wakefield, is scheduled to begin in the spring of 2011, while Phase 3 will extend Highway 5 one kilometre north of Wakefield.

Rita Commandant, a member of SOS, is willing to fight for the spring.

"It's proven good for our health and good for our psyche," she told CBC. "You're not going to take it away without a good fight."

With reporting by Sandra Abma and Alistair Steele