What does a sump pump do in residential plumbing?

A sump pump is specifically designed to manage water accumulation in areas like basements or crawl spaces. Its primary function is to remove excess water that could lead to flooding or water damage in a home. By actively pumping out water that collects in a sump basin, typically located in the lowest part of a building, it helps maintain a dry environment and protects structural integrity.

This function is crucial, especially in regions prone to heavy rainfall or areas where groundwater is high. The other options describe functions not relevant to a sump pump's purpose; filtering water before drainage is typically managed by other systems, adding water to irrigation is done by irrigation pumps, and regulating water pressure is typically handled by pressure regulators or pumps designed for that specific need. Thus, the sump pump’s role is uniquely tied to water removal, making it an essential component of residential plumbing in flood prevention.