Burst pipes — what's actually happening
A burst pipe is when a water supply line ruptures, releasing pressurized water into the structure of your home. The leak rate from a burst supply line — typically 50–80 PSI for residential plumbing — is dramatic: a half-inch supply line can release hundreds of gallons of water per hour until shut off.
The damage compounds in three directions: outward (water spreads across floors and through wall cavities), downward (water travels through subfloor and into ceilings below), and into hidden spaces (insulation, behind cabinetry, into adjacent rooms before being noticed). Most burst-pipe water damage is much larger than the visible surface suggests by the time a tech arrives — moisture meters and thermal imaging surface what's hidden.
Vancouver and Portland metro homes most commonly experience burst pipes during cold snaps when water inside unheated wall cavities, garage walls, and exterior crawl-space lines freezes and ruptures. Older homes (pre-1980 galvanized supply lines, copper that's age-thin) are more vulnerable. Newer homes can also burst when an exposed line in a mechanical room or unheated garage freezes overnight.