The crossword solution for the term 'OVERFLOW CAUSE' is 'CLOG'. Clogs are a common cause of overflows, as they can block the flow of water and cause it to back up. Clogs can be caused by a variety of things, such as hair, soap scum, or other debris that accumulates in pipes over time. Clogs can also be caused by foreign objects that are accidentally flushed down the toilet or sink. In any case, clogs can lead to overflows and should be addressed quickly to prevent further damage.