There is a story to these pictures, if you are wondering what the growth is called, it is referred to as “pipe tuberculation” or “insoluble corrosion residue buildup” and the main issue is that it increases pipe friction losses thus reducing fire flows, but can also ultimately lead to pipe failure. The infrastructure in many of Canada’s cities is failing. This is an example of a pipe that until yesterday was still in service eighty years after it was installed, it has spent it’s life providing water to thousands of residents and aside from annual hydrant flushing, would have received no special treatment – much like every other watermain in every other city in North America. It is interesting to note that some of the technologies that are available to postpone the replacement of pipes in this condition, such as watermain pigging, are still considered relatively novel, and when a pipe is in this condition, money spent on pigging it may be better spent on funding the replacement of it, depending on other factors such as the condition of the road surface and the adequacy of the watermain size.
There is a lot to say about how the infrastructure of North America got to this point and what it will take to fix it, but that is for another post.
If you are interested in the chemical processes that cause this type of corrosion, check out this page on the Fire Protection Engineering Archives.