White Rock was slow to implement a comprehensive backflow protection policy.
Nonetheless it’s now in place. The idea is to keep toxic chemicals from various types of systems including hot water heating systems from entering the drinking supply when there are large pressure drops, thus increasing public protection. Then there are situations like typical exterior hose valves that are considered moderately risky — prohibited in new construction but common in older buildings.
The reason mandated backflow and cross-connection technology should be tested annually is to find devices that need maintenance, repair or replacement .
The chances of a device being out of order (and dangerous) increase dramatically during major pressure regime fluctuations like the one caused by the recent large firefighting effort. Since boiling water does nothing to mitigate toxic chemicals in the water supply—- should this type of situation arise, it seems reasonable to ask people to take precautions by ceasing to drink tap water, not just boil it.