What does well casing include?

Well casing refers to the tubes or pipes installed in a borehole to help stabilize the well structure, protect the water supply from contamination, control groundwater flow, and prevent collapse of the surrounding formations. The components of well casing are critical for ensuring the integrity and functionality of the well.

The correct choice includes both surface casing and inner casing or blank liner. Surface casing is typically installed to protect the well from surface contaminants and to stabilize the upper part of the borehole, while the inner casing or blank liner is placed further down to protect the water-bearing zone and maintain the structural integrity of the well. This combination is essential for effective groundwater extraction and protection, ensuring the well functions properly while safeguarding the quality of water drawn from it.

Other options suggest a limited interpretation of well casing. For instance, mentioning only the inner or outer casing implies a misunderstanding of how these components work together to protect the well and maintain water quality. Focusing solely on plastic linings overlooks the broader structural function provided by both surface and inner casings. Therefore, the comprehensive definition offered by the correct answer captures the full scope and function of well casing in groundwater management.