The infrastructure network that transports safe, clean water around Calgary contains 187 kilometres of pipe similar to the line that suffered a catastrophic break more than two weeks ago, forcing the city’s residents and businesses to cut back on water use and prompting a massive emergency fix-it job.

The city’s Bearspaw South Feedermain, which ruptured June 5, is a prestressed concrete cylinder pipe (PCCP), a design used elsewhere in Calgary and across North America. This type of pipe is known to be vulnerable to major failures, although its engineering has improved since the late 1970s and determining what, precisely, caused the feedermain to crumble may be impossible.