Pipes freeze when they lose heat faster than the surrounding space can replace it, especially in exterior walls, garages, crawl spaces, and exposed runs. Prevention combines insulation, access to warmer air, and targeted steps before a cold snap.
Identify the most exposed pipe runs first
Look for piping in exterior walls, near open vents, under sinks on outside walls, and in unheated spaces. A pipe that has frozen before deserves priority because the same location is likely to remain vulnerable.
Insulate the pipe and reduce cold air leaks
Foam sleeves or other appropriate insulation slow heat loss, but they do not replace sealing cold-air leaks. Seal accessible gaps around penetrations without blocking ventilation the building requires.
Let warmer room air reach enclosed plumbing
During severe cold, opening cabinet doors beneath sinks on exterior walls can let warmer room air reach the piping. Move chemicals out of reach of children and pets if those cabinets are left open.
Follow local guidance on allowing a small trickle
In some systems during exceptional cold, a small trickle can reduce freezing risk, but it depends on climate, plumbing design, and water restrictions. Follow local utility guidance and treat insulation and air sealing as the longer-term fix.