Progressive deterioration

Loss of property due to progressive deterioration is not deductible as a casualty loss. This is because the damage results from a steadily cause or a normal process, rather than from a sudden event. The following are examples of damage due to progressive deterioration:

• termite or moth damage
• destruction done by trees, shrubs, fungus, insects, etc.
• damage done to a water heater that bursts
• weakening of a building due to normal wind and weather conditions