In cold climates with freezing temperatures, water service pipe must be installed not less than how many inches deep and not less than how many inches below the frost line?

• A. Not less than 12 inches deep and not less than 6 inches below the frost line
• B. Not less than 8 inches deep and not less than 4 inches below the frost line
• C. Not less than 6 inches deep and not less than 2 inches below the frost line
• D. Not less than 24 inches deep and not less than 12 inches below the frost line

Answer: (A)

Protecting a water service line from freezing in cold climates means placing the pipe deep enough that winter freezing doesn’t reach it. The frost line is the depth to which the ground typically freezes in your area, and keeping the pipe below that depth helps prevent both freezing and frost heave from lifting the pipe.

The minimum you want is at least 12 inches below the ground surface, and at least 6 inches below the frost line. This places the pipe in unfrozen soil most of the winter and well below the expanding soil layer, ensuring a reliable water supply.

Other options are either not deep enough to prevent freezing or are more than what's needed, which isn’t necessary for this purpose.