Here is the reason why most Vancouver high rise buildings have issues and problems with copper piping and pinhole leaks.
The sources of the Great Vancouver Water District (GVWD) water are rainfall and snow melt runoff that originate in the North Shore Mountains. The water then are collected at the Capilano, Seymour and Coquitlam watersheds.
Due to the geographic nature of the watershed areas, the runoff is unable to absorb mineral content due to the steep mountainous slopes and hard granite rock material. The quality of this water is considered extremely high because of the low mineral content.
Ironically, water with such quality is absorbent to metals therefore becomes corrosive to copper pipes in plumbing systems. Gaseous chlorine is currently used to disinfect the water supply to make it more bacteriological safe for human consumption.
This method of disinfection lowers the pH of an already "soft" water supply. The water becomes even more aggressive and corrosive when heated in the domestic hot water system when the temperature is set high to protect it from growth of the Legionella bacteria.
High velocity also erodes copper pipe and causes pipe wall-thinning. In some cases pitting of copper pipes is related to Microbiological Influenced Corrosion (MIC) that is a waterborne bacterial microbe that settles in the biofilm of the pipe and later colonizes on the interior pipe surface. The bio-waste of the microbes is acidic to copper which result in a cavity in the pipe material. As the nutrient supply continues, the microbe’s colony continues to thrive; increasing the depth of the initial wall cavity resulting in an eventual pinhole.
One of the solutions to this problem, quite inexpensive, is installation of water mineralization and treatment system like Hytec system which adds a microscopic amount of minerals to the water that fully coats the inner copper pipe lining, protect the copper from being leeched by the water. this along with an adjustment in pH, seals the pits and prevents pinhole leaks from occuring.
Other, more expensive solution, is to replace the problematic piping with different thickness materiel pipes that are more resistant to these issues.