The average age of sanitary and storm sewers in Alberta has fluctuated over the past 25 years in line with investment swings, from an all time low of 14.6 years in 1984 to an all time high of 17.8 years in 1997. The most recent trend has been toward larger investments since 2003, which lowered the average age to 16.3 years in 2007.
As a percentage of estimated useful life, Alberta has tended to follow closely the national average in most years since 1990. However, the gap has widened in recent years in favour of the province. In 2007, sewer systems had reached 49% of their estimated useful life, compared with 53% nationally.