A bottom drain is a plumbing feature installed at the deepest part of a koi pond to help remove waste, uneaten food, and debris that settle on the pond floor. It works by drawing water—and with it, heavier particles—into a filtration system, where solids are separated and water is cleaned before returning to the pond. While not absolutely required, a bottom drain makes maintenance easier and supports much better water quality, especially in larger or more heavily stocked ponds.
Without one, waste tends to build up at the bottom, leading to poor water conditions and potential health issues for the fish. Skimmers help remove floating debris, but they don’t reach what settles on the bottom. Installing a bottom drain during the initial pond construction is far simpler than trying to retrofit it later.
