Tap water in apartment buildings freezes due to insufficient pipe insulation, temperature fluctuations, and high water pressure. Older buildings often lack proper insulation, leaving pipes vulnerable to cold air. Sudden temperature drops, especially during winter, exacerbate the risk. High water pressure can force water through pipes faster, increasing the likelihood of freezing in vulnerable areas.

The primary cause is inadequate insulation. Insulation reduces heat loss, maintaining pipe temperatures above freezing. According to the U.S. Environmental Protection Agency (EPA), 15-20% of U.S. homes experience frozen pipes annually, with apartment buildings disproportionately affected due to shared infrastructure. Insulation materials like foam or spray-on coatings are recommended by ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) standards, which suggest R-values of at least 6 for pipes in unheated spaces. Without proper insulation, pipes lose heat rapidly, especially in attics, basements, or exterior walls. For example, a 2021 study by the National Institute of Building Sciences found that 70% of frozen pipes in multifamily buildings were located in poorly insulated areas.

Water pressure plays a secondary role. Excessive pressure forces water through pipes at higher velocities, cooling them faster. The American Water Works Association (AWWA) notes that pressure-reducing valves can mitigate this issue. Temperature fluctuations are critical; pipes near windows or in unheated zones freeze more often. A 2019 report by the U.S. Department of Energy stated that 40% of pipe freezes occur in buildings with frequent temperature swings below 20°F (-6°C). To prevent freezing, apartment managers should insulate pipes, seal gaps, and maintain stable indoor temperatures. Additionally, using heat tape or glycol-based antifreeze in extreme climates can help. Proper maintenance reduces risks, as the EPA estimates 30% fewer freezes in buildings with regular insulation checks. Ultimately, addressing insulation and pressure management is essential to prevent costly repairs and water damage.