Easy Guide: How To Put In A New Kitchen Sink

Can I install a new kitchen sink myself? Yes, most homeowners can successfully install new kitchen sink units with basic tools and some patience.

Putting in a new kitchen sink might seem like a big job. It is not! This kitchen sink replacement guide will walk you through every step. We will help you take out the old sink and fit the new one. We cover both types: the undermount sink installation and the drop-in sink installation. Getting the plumbing for new sink hooked up correctly is key. Let’s start this simple project today.

Gathering Your Tools and Materials

Before starting, make sure you have everything ready. Having the right items makes the job fast and easy.

Essential Tools Checklist

Safety glasses
Pliers (channel locks work best)
Adjustable wrench
Putty knife or scraper
Screwdriver set (flathead and Phillips)
Caulk gun
Silicone sealant (kitchen and bath grade)
Bucket and old towels (for water spills)
Safety gloves

Necessary Materials

The new kitchen sink
New sink clips or mounting hardware (often comes with the sink)
Plumber’s putty or silicone caulk (check sink instructions)
New drain assemblies or strainers (if needed)
Supply lines (if installing kitchen faucet with sink at the same time)

Step 1: Removing the Old Kitchen Sink

We must safely get rid of the old unit first. Turn off the water! This is the most important safety step.

Shutting Off Water and Power

Locate the shut-off valves under the sink. These control the hot and cold water lines.
Turn both valves clockwise until they stop.
If you have a garbage disposal, unplug it from the wall outlet under the sink. If it is hardwired, turn off the power at the main breaker box.

Disconnecting the Plumbing

This part handles connecting kitchen sink drain lines. Be ready for some water to spill.

Place a bucket right under the P-trap (the U-shaped pipe).
Use channel locks or pliers to loosen the slip nuts on the P-trap. Turn them counter-clockwise.
Carefully remove the P-trap and let any trapped water drain into the bucket.
Disconnect the old supply lines from the faucet shanks. Use a wrench if they are too tight.
If you have a disposal, twist the mounting ring to detach the disposal unit from the old sink flange. Set the disposal aside safely.

Freeing the Old Sink Basin

How you remove the sink depends on if it is a drop-in or undermount style.

For Drop-In Sinks:

These sinks sit on top of the counter. They are held by clips and sealant.
Use a sharp putty knife to cut through the old caulk or silicone around the rim where the sink meets the countertop. Work slowly all around the edge.
Look under the counter for mounting clips. Use a screwdriver or socket wrench to loosen and remove all these clips.
Once the clips and caulk are free, gently push up from below or lift carefully from above to free the sink. It might be heavy.

For Undermount Sinks:

These sinks are glued and clipped underneath the counter.
Cutting the sealant is crucial. Use the putty knife to cut all the caulk where the sink rim meets the stone or laminate.
Remove the heavy-duty mounting clips that secure the undermount sink installation.
Have a helper ready. Gently push the sink down and away from the counter. Be careful not to chip the counter edge.

Step 2: Preparing the New Sink and Countertop

The success of your project relies on clean surfaces and correctly pre-installed parts.

Cleaning Up the Sink Opening

Scrape off all old putty, caulk, and grime from the countertop opening. Use mineral spirits if needed to remove sticky residue.
Wipe the area dry. A clean surface helps the new sealant stick well.

Pre-Installing Components (Crucial Step)

It is much easier to installing kitchen faucet with sink before you put the new basin in place.

Installing the Faucet

Read your new faucet instructions.
Place the faucet base plate (if used) over the faucet holes in the new sink deck.
Feed the faucet supply lines and mounting shank(s) through the holes from the top.
From underneath the sink, slide on any washers and then tighten the mounting nut onto the shank. Use a basin wrench if the space is tight. Make sure the faucet is straight before fully tightening.

Installing the Strainer/Drain Flange

This involves sealing kitchen sink flange correctly to prevent leaks.

Apply a thick rope of plumber’s putty around the underside edge of the new sink strainer basket flange.
Press the strainer assembly firmly into the drain hole of the kitchen sink basin mounting.
From underneath, slide on the rubber gasket, then the friction ring, and finally the locknut.
Hand-tighten the locknut first. Then use channel locks to tighten it further until the putty squeezes out around the top flange.
Wipe away the excess putty from the top. Do not overtighten the locknut, as this can crack ceramic or stainless steel sinks.

Replacing kitchen sink disposal (If Applicable)

If you are installing a new disposal or reusing the old one:

Apply plumber’s putty around the flange opening of the disposal mount.
Press the new mounting flange into the drain hole.
From below, secure the mounting ring and tighten the screws according to the disposal instructions.

Step 3: Mounting the New Kitchen Sink Basin

Now it is time to set the new sink into the counter opening. The method differs based on the sink type.

Mounting a Drop-In Sink Installation

A drop-in sink (also called a top-mount) rests on the countertop.

Apply a continuous bead of 100% silicone sealant along the underside rim of the new sink. This creates the watertight seal.
Carefully lower the new sink into the counter opening. It should sit flush.
Check the alignment from all sides. You have only a few minutes before the silicone sets slightly.
Reach under the counter and install the provided mounting clips. Screw them firmly against the underside of the countertop, pulling the sink down tight against the sealant. Space the clips evenly.
Wipe away any silicone that squeezed up around the rim immediately with a damp cloth.

Undermount Sink Installation

This takes more support and precision. The sink is mounted beneath the counter surface.

If your countertop is solid material (like granite or quartz), the mounting clips will screw directly into the material or into a wooden sub-structure beneath.
If your counter is laminate or wood, you often need a separate mounting frame or bracket system provided by the sink manufacturer.
Apply a generous, even layer of specialized epoxy or silicone adhesive to the rim of the sink where it contacts the underside of the counter.
Lift the sink into place. This is heavy work; use clamps or temporary supports if possible to hold it firmly against the bottom of the counter.
Install the mounting clips. Tighten these clips slowly and evenly. They pull the sink tightly against the adhesive and counter surface.
Allow the adhesive to cure fully before proceeding. Check the silicone or epoxy package for the required curing time—usually 12 to 24 hours. Do not connect the drain or use the sink during this time.

Step 4: Final Plumbing Connections

This involves finishing the plumbing for new sink setup. We will now connect the supply lines and the drain system.

Connecting Water Supply Lines

If you did not installing kitchen faucet with sink earlier, do that now (see Step 2).
Connect the flexible supply lines extending from the new faucet to the hot and cold shut-off valves below the sink.
Hand-tighten the connections first. Then, use an adjustable wrench to give them a final quarter turn. Do not overtighten supply lines, as this can damage the rubber washers inside.

Connecting Kitchen Sink Drain

This step hooks up the basket strainer to the P-trap.

If you installed a new disposal, reconnect the disposal unit to the mounting ring according to its manual.
Align the P-trap (the U-shaped pipe) with the tailpiece coming down from the sink strainer.
Slide the slip nuts and washers onto the pipe ends.
Connect the pieces, making sure the washers are seated correctly inside the joints.
Hand-tighten all the slip nuts. Give them a slight turn with the pliers until snug.

Step 5: Testing for Leaks and Finishing Touches

We must ensure our work is waterproof before calling the job done.

Testing Water Connections

Slowly turn the hot and cold water shut-off valves back on. Listen for rushing sounds.
Check the connections where the supply lines meet the shut-off valves. If you see drips, gently tighten the connections a little more.
Turn on the faucet. Let the water run hot and cold for a minute.
While the water runs, shine a flashlight under the sink and look closely at all supply line connections and the faucet base.

Testing the Drain System

This is critical for sealing kitchen sink flange integrity.

Plug the new sink drain(s) and fill the basin halfway with water.
Pull the stopper and let the water rush out quickly.
While the water drains, inspect every connection on the drain pipe system—the tailpiece, the P-trap, and the connection to the wall pipe.
If you see drips, gently tighten the corresponding slip nut. A slow drip usually means the washer is not perfectly centered or the nut needs a slight turn.
For disposals, run the disposal briefly while water is flowing to ensure the seal where it meets the strainer flange is tight.

Final Cleanup

Allow the exterior silicone caulk (if used for a drop-in) to cure fully before heavy use. Check the manufacturer’s recommended cure time.
Wipe down the sink, faucet, and surrounding area.

You have successfully completed your kitchen sink replacement guide project!

Special Considerations for Different Sink Types

While the basic process is similar, sink materials and types have unique needs during kitchen sink basin mounting.

Stainless Steel vs. Composite Granite Sinks

Feature	Stainless Steel Sinks	Composite Granite Sinks
Weight	Generally lighter	Significantly heavier
Mounting Support	Standard clips usually suffice	Needs very strong support, especially for undermount
Sealing	Silicone works well	Silicone is essential; putty may not adhere as well long-term
Noise	Can be loud; may require sound-dampening pads	Naturally quieter

Undermount Sink Installation on Solid Surfaces

When installing an undermount sink in granite or quartz, clamps and epoxy are non-negotiable. These counters are heavy, and the only thing holding the sink up is the adhesive and the clips pulling it tight against the stone. Do not skip the curing time for the adhesive.

Drop-in Sink Installation in Laminate Countertops

If your counter is laminate, ensure you seal the edge of the cut opening thoroughly with sealant before dropping the sink in. Laminate absorbs water easily, and any breach in the seal will cause the particleboard core to swell and destroy the counter edge around the sink.

Dealing with Garbage Disposals During Replacement

When replacing kitchen sink disposal, pay close attention to the mounting collar system. Most disposals use a three-bolt mounting system.

Remove the old collar assembly entirely from the sink flange.
Clean the drain hole thoroughly.
Install the new flange (if the old one is damaged or incompatible) using plumber’s putty, ensuring a perfect seal.
Attach the new mounting ring and tighten the bolts.
Twist the new or old disposal onto the mounting assembly until it locks firmly.

Tips for Installing a Kitchen Faucet Separately

Sometimes, you only replace the faucet and not the whole sink. Installing kitchen faucet with sink parts separately requires reaching into a tight space.

Always disconnect the water lines first.
Use a basin wrench. This specialized tool has a long, thin handle and a pivoting jaw perfect for reaching the nuts that hold the faucet shanks in place from underneath the sink deck.
When threading the new faucet nuts, ensure the faucet body remains straight on the top deck before tightening completely.

Frequently Asked Questions (FAQ)

What is the difference between a drop-in and an undermount sink?
A drop-in sink has a rim that rests on top of the counter. An undermount sink is mounted below the counter, so the counter edge meets the sink basin directly.

How much silicone sealant should I use for sealing kitchen sink flange?
For a drop-in sink rim, use a continuous rope of sealant about the thickness of a pencil. For an undermount adhesive application, apply a thick, continuous bead (about 1/4 inch thick) to the entire perimeter of the sink rim.

How long do I wait before using my new sink after installation?
If you used plumber’s putty for drain connections, you can test the drains right away. If you used silicone or epoxy adhesive for undermount sink installation, you must wait for the product to cure, typically 12 to 24 hours, before running water or putting weight in the sink.

What tool is best for connecting kitchen sink drain pipes?
Channel lock pliers or large adjustable wrenches are best for tightening the plastic slip nuts on the drain pipes. Remember, these joints seal using washers; excessive force can crush the washers or crack the plastic.

Can I reuse my old supply lines when I install new plumbing for new sink?
It is generally recommended to replace supply lines when installing a new faucet or sink. Old lines may have mineral buildup or weakened connections, increasing the risk of a future leak.

Do I need plumber’s putty or silicone for the drain strainer?
Most modern drain strainers recommend plumber’s putty for the flange sealing where it contacts the sink basin. However, check your sink or strainer instructions, as some manufacturers specify silicone for certain materials.