Which of the following would NOT be considered a flood?

A sewer backup would not typically be classified as a flood. Flooding is primarily defined as an overflow of water onto normally dry land. This can include water from various sources, such as rivers, lakes, or tidal waters. The key aspect of a flood is that it involves a widespread inundation that affects properties or land outside of their normal water boundaries.

In contrast, a sewer backup is localized and generally pertains to water and sewage that backs up from the municipal sewer system into homes or properties, rather than overland flooding from bodies of water. This type of event is usually covered under different insurance policies, such as homeowner policies that address plumbing issues, rather than flood insurance.

The other options presented directly involve the overflow of water from natural bodies or conditions that meet the definition of flooding. For example, runoff of surface waters can cause flooding when heavy rains or storms overwhelm drainage systems. Overflow of tidal waters refers to the inundation of land caused by high tides or storm surges. Mudslides may result from heavy rainfall or flooding but are specifically categorized as geological hazards rather than flood events.