Triple Kitchen Sink Installation Guide

Installing a three bowl sink is like installing any standard sink. The rectangle design – as opposed to a batwing corner sink or round sink, for example – makes it easy to cut the sink opening.

This DIY sink installation overview will help you decide whether or not to do the work or hire a professional and to know what they should be doing if you do hire someone.

kitchen sink installing

To install a triple sink, you’ll need:

  • Tape measure
  • Marking pencil
  • Jigsaw or circular saw
  • Wood screws
  • Painter’s tape
  • Silicone sink caulk
  • Drill/driver and ¼” drill bit
  • Screwdriver
  • Safety glasses or goggles

Cutting the Sink Hole in the Countertop

This is the make or break task of sink installation. If you do it right, you’ll save yourself some money. Done incorrectly, you can ruin the countertop.

If you’re installing granite, quartz, solid surface or other expensive and difficult to cut material, ask the retailer if the sink hole can be cut at the factory and how much extra that step will cost. That might be a good option. In fact, it’s standard on most countertops. This goes double when installing an undermount sink, since the countertop edge will be exposed.

If you do cut the hole yourself, these tips will help.

  • Position the template on the countertop or the substrate (if you’re installing tile) exactly where the sink will go, and use painter’s tape to secure it
  • If using a jigsaw, use the drill and ¼” bit to create a starter hole
  • Use the template as a guide, cutting along the line all the way around
  • Tip: The material you’re removing should be supported from below near the end of the cut, so that it won’t break off and splinter the countertop material

Installing a Drop-in Sink

This is an easy task for those with basic DIY experience.

  • Run a ¼” bead of silicone caulk around the edge of the sink hole
  • Drop in the sink, and push it down firmly before wiping off excess silicone
  • From beneath, install and tighten the clamps supplied to secure the sink to the countertop
  • Install any additional support brackets required
  • Hook up the disposer, typically to the center bowl
  • Note: If you’re installing a cast iron sink, see our Cast Iron Kitchen Sink Installation Guide for instructions on installing the extra support required for their weight
  • Install the drain lines

Installing an Undermount Triple Sink

Here’s how to install a triple sink beneath the countertop:

  • Turn the countertop or substrate upside down
  • Run a ¼” bead of silicone caulk around the underside edge of the sink hole
  • Set the sink onto the countertop or substrate, and press down firmly, making sure the sink is located exactly where it needs to be
  • Install the clamps used to secure the sink to the underside of the countertop
  • Install the countertop or substrate and the sink together onto the base cabinets
  • Install any additional support required for the sink
  • Tip: Even if additional support isn’t required, some installers recommend adding 1”x1” or 1”x2” supports for both sides of the sink and attaching the supports to the front and back of the sink cabinet
  • Note: See our Cast Iron Kitchen Sink Installation Guide for instructions on supporting these heavy sinks.
  • Install the drain lines

The Cost to Install a Triple Kitchen Sink

Sink installation is often included in the cost of countertop installation. However, for just sink installation, expect estimates in this price range:

  • Triple sink installation cost: $125-$450

Installing the sink and three drain lines, the simplest installation, will be relatively inexpensive. The more appliances such as a garbage disposal and tankless water heater are included, the higher the sink installation cost will be.

Triple Sink Installation FAQ

This triple sink Q&A covers common questions.

I’m having an undermount sink installed and have to decide on the reveal. What is best?

First, let’s explain what the reveal is for readers unfamiliar with the term. An undermount sink hole can be cut to slightly overlap the top sink edge (negative reveal), be flush with the sink edge (zero reveal) or allow the sink edge to show (positive reveal).

Most choose flush or negative reveal. A positive reveal – in which the sink hole is slightly larger than the sink – allows the top edge of the sink to show. While some consider this visually appealing, and code in some places requires it so that all food prep area edges can be cleaned, most who choose it aren’t happy with it in the long run. First, the visible sink edge collects food and eventually food stains. Secondly, a revealed edge is at risk for being chipped. Finally, the caulk between the sink edge and countertop is visible, and the caulk eventually yellows and looks dingy or stained.

A negative reveal is nice in that it allows you to brush crumbs and other debris off the countertop and right into the sink without them clinging to the side of the bowl. Once caution about a negative reveal is that the underside of the overhang can be a place where mold grows. You should clean it regularly with a mild antibacterial solution.

I’m installing a 45” stainless steel sink. Does it need extra support?

Even though stainless steel is relatively light, the width of the sink is a concern. Many professional installers would add supports beneath the sink– supports that attach to the sink cabinet front and back rather than to the countertop.

Related Content in this Series

View other guides in this series which you may find useful.