It may seem puzzling to some that a city in lake-rich Ontario is concerned about running low on water. But Guelph has a problem: with a population of nearly 120,000 people, it is the largest municipality in Canada that relies solely on groundwater. And the city's growth shows no sign of abating.
To head off the prospect of water shortages, the city has adopted an aggressive conservation strategy and a rebate program to encourage residents to install systems that collect shower water and treat it with chlorine for toilet flushing.
Wayne Galliher, Guelph's water-conservation project manager, said it's too soon to tell whether the municipality would consider making grey-water recycling – the reuse of bath, sink and laundry water – mandatory in new construction. Maintaining the systems has been an issue for some of the 28 homeowners involved in the city's pilot project, but demand for water has dropped: a 25-per-cent reduction in older houses, 15-per-cent drop in newer ones.
"At this point, we're still investigating the technology itself," Mr. Galliher said. "From a water- and wastewater-servicing perspective, we want to have the assurances that what's working today is working tomorrow and down the road as well."
Few Canadian municipalities have turned to recycling wastewater. But interest is rising, especially in fast-growing regions confronting the potential of water shortages, such as the Prairies, swaths of British Columbia's interior, and the Southern Ontario community of Guelph.
A new report from the National Research Council in the United States will likely bolster the case for recycling wastewater. The government-sponsored report suggests there's little reason to be squeamish about reusing wastewater – even from toilets – because of advances in treatment technologies.
In some cases, properly treated municipal sewage may be safer to drink than water from conventional sources, the 14-member panel of engineering and water experts concluded. Reusing treated effluent, the panel added, could greatly boost America's water resources at a time when climate change threatens to reduce supplies in some regions.
"With time, it will be essential everywhere," said Pierre Bérubé, a University of British Columbia associate civil engineering professor whose research includes wastewater reuse. "If you look at Florida, southern California and much of Australia, they've had to go that way because there, they don't have a choice. The economics dictate that that's the thing to do."
Municipalities in parched U.S. regions have long reused effluent to irrigate golf courses, parks and farmland and to cool industrial equipment, but few have turned to sewage for drinking water. The need, though, is growing.
The village of Cloudcroft in the mountains of New Mexico has started blending treated effluent with water from springs and wells. The mixture is stored in a tank for several weeks, treated again, tested and piped into homes.
Next door in Texas – grappling with one of its worst droughts – construction has started on the state's first plant designed to turn sewage into drinking water. When completed later this year, the facility will supply four bone-dry west Texas cities with much-needed water.
There are no such plans in Canada, but one form of recycling that is expected to grow is reusing grey water for toilet flushing, as is happening in Guelph. A national guideline on the practice was created two years ago, the country's first rules on domestic water reclamation. Provinces, however, can choose whether to adopt the guideline, and the lack of a certification process for grey-water treatment systems has been a stumbling block.
Cate Soroczan, a senior water researcher with the Canada Mortgage and Housing Corporation, is chairing a committee examining the performance of water reuse systems. The Canadian Standards Association hopes to develop a protocol for certification this year.
Ms. Soroczan believes certification will make the public and regulators more comfortable with wastewater recycling. Canada has had residential grey-water pilot projects before, but few are in operation today, in part because of maintenance challenges.
Reusing shower water in toilets could be an option for hockey arenas in Manitoba, although initially a grander scheme was envisioned. Instead of simply letting water drain away from locker-room showers at a Winnipeg hockey arena, a plan was hatched to capture that water, filter it, and use it to make ice.
If it worked, the provincial government had hoped the water-saving idea could be transplanted to every skating and curling rink in Manitoba. But preliminary results of a study examining the concept have raised health and financial questions and uncovered one insurmountable obstacle: using wastewater to create ice isn't allowed under Canada's plumbing code.
"It's certainly disappointing, because the [water]savings and green aspect of it would just be fabulous," said Jacques Levesque, general manager of Winnipeg's Dakota Community Centre, which is participating in the soon-to-be-completed study. "But I'd rather be safe than sorry."