What is the process of groundwater leaking into systems through joints or cracks called?

The process of groundwater leaking into systems through joints or cracks is known as infiltration. This term describes the movement of water from the surface into the soil and into underground aquifers. Infiltration occurs when precipitation or surface water percolates through the ground and enters the subsurface, specifically through openings that may not be watertight.

In the context of maintenance work, understanding infiltration is crucial because it can affect plumbing systems, drainage, and structures. Addressing issues related to infiltration ensures that groundwater does not compromise structural integrity or lead to other water-related problems.

Other terms, such as emulsion, refer to mixtures, often of liquids that do not typically blend; exfiltration is the opposite of infiltration, where water is expelled from the ground or systems. Infusion generally deals with the introduction of a substance into another, which is not applicable here. Thus, infiltration is the correct term for the process described in the question.