Ontario taxpayers are shelling out $700 million a year for drinking water that never reaches their taps, according to a study released Wednesday by a group representing management and labour groups in the construction industry.

The Residential and Civil Construction Alliance of Ontario says it found that municipal water systems in the province experience leakage rates ranging from 10 to 50 per cent.

Conservatively estimated, about one-quarter of the drinking water in Ontario is pumped into the ground, the alliance says. Annually, it says, the province loses 327 million cubic metres of water, enough to fill about 131,000 Olympic-sized swimming pools.

The alliance says there are a host of costs associated with leaky pipes:

  • Leakage can cause basement flooding, erosion of foundations, service disruptions and in extreme cases, sink holes. Businesses and homeowners are affected.
  • Treated water contains chlorine, and this can flow into sensitive bodies of water.
  • Leaky sewer lines result in effluent being discharged into the environment.

University of Toronto civil engineering professor Tamer El-Diraby, lead author of the report, says it is no longer good enough for governments to consider only the short-term operating impacts of infrastructure projects.

"When governments evaluate return on investment, they must also assess the environmental and social benefits," he says. "The logical conclusion is for governments to aggressively tackle the rehabilitation of leaking pipes."

The alliance says fixing the leaks would mean less energy is used to pump water through municipal water systems.