of water infrastructure statistics. According to McGill University (1996), in 1995 the average age of municipal sewage treatment infrastructure in Canada was just under 25 years; the average age of municipal storm sewers was about 32; and municipal sanitary and combined sanitary and storm sewers was about 41. However, in Toronto for example, 17% of water mains are 80-100 years old and 7% are even older. High population growth has been focused on a limited number of large metropolitan centres. About two-thirds of the population live in these areas; the largest seven account for 45% of the total population. Water infrastructure was well maintained until the 1970s, due to good economic conditions and the fact that many of the facilities were built after 1945 and SO relatively new (Infrastructure Canada, 2004). Most agree that since then there has not been the required investment in the maintenance of the infrastructure. As a result, deterioration of water infrastructure has become a significant problem. It has been estimated that to repair Ontario's water mains costs CAD 40 million a year, that water losses are around 40%, and that 25% of the water system must be replaced and 50% restored over the next 60 years (Infrastructure Canada, 2004). According to a 1996 survey of 167 Canadian municipalities, 59% indicated that water distribution infrastructure was in need of repair. The situation for wastewater infrastructure was worse: 68% of the sewer systems were reported to be in need of repair. For example, in Ontario in 2002, 61% of water treatment works failed inspections and in 2001, 101 sewage treatment works violated provincial laws or guidelines (Brubaker, 2003). At the same time, new standards, design requirements, regulatory demands and stricter environmental and health regulations have increased both the need for upgrading and capital and operational costs. Three decades of deferred maintenance work have created a situation where deterioration will escalate exponentially if no action is taken (Mirza and Haider,