A 1.5-inch kitchen sink waste and overflow kit is an essential plumbing assembly that ensures efficient drainage and prevents overflow in ceramic, stainless steel, or composite sinks. Central to the kit is the waste (or drain), which includes a strainer or plug mechanism fitting snugly into the sink’s basin hole—typically 83–90 mm in diameter—allowing water to drain freely while catching large debris.

The overflow component features a pipe (usually PVC or metal) that connects an upper overflow inlet inside the sink to the drainage system. This prevents accidental flooding if the basin becomes too full. Kits often include gaskets, seals, a tailpiece, and connecting fittings to guarantee a watertight installation.