What is the minimum distance from the top of the well casing to the regional flood level?

• A. Two feet
• B. Six inches
• C. Four feet
• D. One foot

Answer: (A)

Keeping the top of the well casing at least two feet above the regional flood level helps protect the well from floodwaters and the contaminants they can carry. If floodwaters reach or exceed the level of the well, they can infiltrate around the casing or vent, pushing surface water and microbes into the well and potentially compromising the entire water supply. The regional flood level is the expected high-water mark for floods in that area, so providing a two-foot clearance creates a safety margin against unexpected rises, debris, and wave action during flood events.

Six inches or one foot would not provide enough clearance for typical flood surges, and four feet is more than the minimum needed in most codes. Therefore, the minimum distance is two feet.