There are four common types of mounting installations for a kitchen sink into the countertop: drop-in, undermount, dual mount, and farmhouse.
DROP-IN
Drop-in installation—also known as top-mount or self-rimming installation—is a method where the sink is “dropped” into a pre-cut hole on the countertop. The sink’s outer rim sits on top of the counter surface, securing the unit in place and supporting its weight. It is one of the most common and easiest types of kitchen or bathroom sinks to install.
UNDERMOUNT
Undermount installation is a sink mounting method where the sink is installed beneath the countertop, creating a seamless, rimless look. The edge of the countertop is exposed, and the sink is secured from below using brackets, clips, or adhesives.
DUAL MOUNT
Dual mount installation refers to a versatile sink design that allows the sink to be installed either as a drop-in (top-mount) or undermount—depending on your countertop material, style preference, or installation needs.
If you go with a tile or laminate countertop, you can use it as the drop-in style because of its ultra-flat sink rim.
As an undermount, the top side of the ultra-flat rim attaches easily to the bottom of solid-surface countertops. This flat rim can help seal the edges of the sink hole, and the low-profile flat rim also makes it easy to wipe from the counter directly into the sink.
FARMHOUSE
Farmhouse sink installation, also called apron-front installation, involves a sink that slides into a custom-cut cabinet base, with the front of the sink (the “apron”) exposed. Unlike drop-in or undermount sinks, farmhouse sinks require cabinet modification or specially made farmhouse sink base cabinets.