To prevent freeze damage, how deep must the top of the pipe be buried below the frost line?

The requirement for burial depth of pipes to prevent freeze damage is influenced by the frost line, which is the depth at which soil temperatures remain at or above freezing during winter months, preventing water in the ground from freezing. In many jurisdictions, burying pipes to a depth of 1 foot (12 inches) below the frost line is commonly accepted as sufficient to protect against freeze damage.

Burying pipes below this designated depth creates an effective buffer against extreme temperature changes and minimizes the risk of the water inside the pipes freezing. Local codes or climatic conditions can vary, so it's important to consult applicable regulations or guidelines specific to the location when determining the exact depth. However, 1 foot is a widely recognized standard for minimizing freeze risk.

The other options suggest shallower depths, which may not adequately protect the pipes in many climates, leading to a higher risk of freeze damage in colder months. Thus, the choice of 1 foot aligns with established practices in the industry for safeguarding against such conditions.