How Do I Replace A Kitchen Sink: Easy Guide

Yes, you can replace a kitchen sink yourself! This DIY sink replacement project is very doable for most homeowners. This guide will show you how to safely remove your old sink and install a new one. We will cover everything from prepping the area to finishing the final plumbing under sink connections.

Getting Ready for Your Kitchen Sink Swap

Swapping out your kitchen sink takes careful planning. Rushing this job leads to leaks and frustration. First, decide on the type of sink you want. Do you want an undermount sink replacement, which mounts below the counter? Or maybe a drop-in sink installation, which simply drops into a hole in the countertop? Knowing this affects how you remove the old unit.

Tools and Materials Checklist

Gathering everything beforehand saves time. Here is what you will need for a successful replacement:

New sink and faucet set
Plumber’s putty or sealant for kitchen sink (like silicone caulk)
Basin wrench (very important for tight spots)
Adjustable wrenches
Screwdrivers (flathead and Phillips)
Putty knife or scraper
Safety glasses and gloves
Buckets and old towels
Utility knife
Safety glasses

Shutting Off the Water

Safety first! Before touching any pipes, turn off the water supply.

Locate the shut-off valves under the sink. They are usually chrome handles leading to the hot and cold water lines.
Turn both handles clockwise until they stop.
Turn on the old faucet to drain any remaining water pressure in the lines. Let the water stop dripping completely.

Taking Out the Old Sink

Removing old kitchen sink units can sometimes be the trickiest part. The difficulty depends on how the previous owner installed it.

Disconnecting the Plumbing

This involves several steps to separate the sink basin from the rest of the house plumbing.

Disconnecting the Faucet

If you plan to replace kitchen faucet too, now is the time to take it off.

Use your basin wrench to reach up behind the sink.
Loosen the nuts holding the faucet shanks in place. These nuts are often hard to reach.
If the faucet has a sprayer, detach its hose.
Lift the old faucet assembly out from the top of the sink.

Disconnecting the Garbage Disposal

If you have a garbage disposal unit, you must disconnect garbage disposal before lifting the sink.

Check under the sink for the disposal’s power cord. Unplug it from the wall outlet if it plugs in. If it is hardwired, you must turn off the power at the main circuit breaker box.
Use a screwdriver to loosen the mounting ring screws that hold the disposal to the sink drain assembly.
Twist the disposal unit counter-clockwise to detach it from the mounting flange. Be ready; it might be heavy.
Set the disposal aside safely.

Detaching the Sink Drain

The drain assembly also needs removal.

Place a bucket under the P-trap (the curved pipe).
Use channel locks or an adjustable wrench to loosen the slip nuts on the trap and the tailpiece connecting to the sink drain. Water will likely spill out, so have towels ready.
Remove the old strainer basket or drain flange from the sink bowl itself. Use a putty knife to scrape away old caulk around the drain opening.

Separating the Sink from the Countertop

This step depends heavily on your sink type.

For Drop-In Sinks (Top Mount)

Drop-in sinks sit on top of the counter and are usually held by clips or sealant.

Look underneath the sink rim. You will usually see small metal clips screwed into the underside of the countertop, holding the sink down.
Use a screwdriver or nut driver to loosen and remove these clips.
Use a sharp utility knife to carefully cut through the bead of old caulk or sealant for kitchen sink around the entire rim where the sink meets the counter. Cut slowly to avoid scratching the counter surface.
Have a helper assist you. Gently pry up the sink from underneath using a wooden wedge or a piece of wood spanning the counter edges. Lift the sink straight up and out.

For Undermount Sinks

An undermount sink replacement is harder because the sink is glued and screwed underneath the counter material.

If the sink is supported by clips, remove these first, just like with a drop-in sink.
If the sink is attached using strong adhesive (common with granite or stone counters), you must use a stiff putty knife or thin pry bar. Work slowly around the edges, gently breaking the adhesive bond. Be extremely careful not to chip the stone countertop.
Once the adhesive seal is broken, carefully lower and remove the heavy sink basin.

Preparing the Space for the New Sink

The space under the counter must be clean before setting the new sink.

Cleaning the Counter Opening

Scrape off all remaining old caulk, putty, or adhesive residue from the countertop opening. A clean surface is vital for a good seal with the new sink. Wipe the area clean with rubbing alcohol to ensure no grease remains.

Preparing the New Sink

If you are not installing a new faucet now, you might install the drain hardware first. It is much easier to work on the sink basin when it is outside the cabinet.

Installing the Faucet

It is best practice to install kitchen sink components like the faucet and sprayer before setting the basin into the counter.

Place the new faucet assembly onto the sink deck holes.
From underneath, secure the mounting nuts tightly using your basin wrench. Do not overtighten plastic parts.
Connect the water supply lines (hot and cold) to the new faucet shanks. Hand-tighten first, then use a wrench for a final quarter turn. Do not crush the rubber gaskets.

Installing the Sink Strainer/Drain Flange

This part requires plumber’s putty or a specialized gasket.

Roll a thin rope of plumber’s putty (about the thickness of a pencil) and wrap it completely around the underside lip of the new drain flange.
Press the flange firmly into the drain opening from the top of the sink basin.
From underneath, slide on the rubber gasket, followed by the friction ring, and finally, tighten the locknut until the putty squeezes out around the top edge.
Wipe away the excess putty immediately.

Installing the New Sink

This is where your type of sink matters most for the install kitchen sink procedure.

Drop-In Sink Installation Steps

This is usually the easiest method for a DIY homeowner.

Apply a generous bead of sealant for kitchen sink (silicone caulk) to the underside rim of the sink basin. This creates the watertight seal against the countertop.
Carefully lower the new sink into the countertop opening. Make sure it sits evenly and squarely.
If your sink has mounting clips, install them now. Position the clips evenly around the perimeter and tighten them just enough to hold the sink firmly against the counter edge. Do not overtighten, as this can warp the sink rim or crack the counter.
Wipe away any silicone sealant that oozes out immediately with a damp cloth.

Undermount Sink Replacement Steps

This requires more precision, especially if working with heavy stone.

Apply a thick bead of high-strength silicone adhesive (specific for stone or plumbing use) to the mounting surface on the countertop where the sink lip will rest.
Lift the heavy sink into place beneath the counter opening. This usually requires two strong people.
Align the sink precisely with the edge of the cutout.
Secure the sink using the specialized mounting clips or brackets designed for undermount sinks. These brackets usually screw into the underside of the countertop. Tighten them slowly and evenly.
Allow the adhesive to cure fully, according to the manufacturer’s instructions, before connecting the plumbing or using the sink. This waiting time is crucial for sink stability.

Final Plumbing Connections

Now we finish connecting the essential parts of the plumbing under sink.

Connecting the Faucet Supply Lines

If you replace kitchen faucet along with the sink, these lines should already be attached to the faucet body.

Connect the faucet’s flexible supply lines to the main shut-off valves coming out of the wall or floor.
Hand-tighten the compression nuts onto the valve stems.
Use a wrench to tighten them about one full turn more. Be careful not to overtighten, which can damage the rubber seals inside the connection.

Installing the Garbage Disposal

If you removed a disposal, reattaching the new one (or the old one) follows the same general steps in reverse.

Ensure the rubber gasket is properly seated on the new drain flange installed in the sink.
Lift the disposal unit and align the three mounting tabs on the disposal collar with the tracks on the sink flange.
Twist the disposal clockwise until it locks securely into place. The locking ring should be snug.
Reattach the electrical connection. Plug it in or turn the breaker back on, only after all water connections are secure.

Kitchen Sink Drain Installation and P-Trap Connection

Proper kitchen sink drain installation ensures no slow leaks develop over time.

Reattach the tailpiece (the straight pipe coming down from the sink drain) to the P-trap assembly.
Connect the P-trap back to the main waste line coming out of the wall.
Hand-tighten all slip nuts. Then, use channel locks to give them a final snug turn. Do not wrench them too hard, as plastic pipes can crack easily.

Testing for Leaks

This final test is critical to confirm your DIY sink replacement was successful.

Ensure all drain connections are tight.
Slowly turn the hot and cold water shut-off valves back on (counter-clockwise). Listen for any hissing or rushing sounds indicating a major leak.
Turn on the new faucet and let the water run for several minutes. Check the connections where the supply lines meet the faucet and the shut-off valves. Dry all connections thoroughly and look for drips.
Fill the sink basin with water completely. Pull the stopper and let the water rush down the drain quickly.
Immediately check all drain connections below the sink—the tailpiece, the P-trap, and where the waste line enters the wall. Use dry paper towels to feel for any moisture. If you find a drip, gently tighten the corresponding slip nut a little more, then retest.

Sink Material Comparison

Choosing the right sink material affects both the installation process and long-term durability.

Sink Material	Pros	Cons	Installation Note
Stainless Steel	Durable, affordable, easy to clean	Can scratch, noisy (needs sound dampening pads)	Works well for drop-in or undermount.
Cast Iron (Enamel)	Very tough, classic look, quiet	Extremely heavy, enamel can chip	Requires strong support; often heavy for undermount sink replacement.
Composite Granite	Stain-resistant, modern look	Expensive, requires very firm clamping	Excellent for drop-in sink installation.
Fireclay	Very durable, classic farmhouse look	Very heavy, less chip resistant than cast iron	Requires solid base support.

Specialized Installation Tips

Different sinks require slightly different approaches for the best result.

Tips for Drop-In Sink Installation

Because these sinks rely on a rim resting on the counter, proper sealing is everything.

Use a high-quality 100% silicone sealant for kitchen sink. Avoid cheap acrylic caulk.
Ensure the mounting clips are spaced evenly. Uneven pressure causes the seal to fail over time.

Tips for Undermount Sink Replacement

The structural integrity of the hold is paramount here.

If you are working with laminate counters, undermount sink replacement is often not recommended, as the particle board can swell if water gets in. Solid surfaces like granite or quartz are best.
Use clips or support rods specifically designed for the weight of your sink material. Heavy cast iron sinks may require extra bracing supports under the cabinet floor.

Replacing the Faucet Simultaneously

It is almost always easier to replace kitchen faucet while the sink is out of the counter. If you decide to replace the faucet later, you will have to crawl under the sink again, often scraping your back in the process, to reach the mounting nuts. Taking care of both jobs at once minimizes disruption.

Frequently Asked Questions (FAQ)

How long does a DIY sink replacement take?

For an experienced DIYer replacing a similar sink type (e.g., drop-in for drop-in), the process can take 3 to 5 hours. If you are switching from a drop-in to an undermount sink replacement, or if the old sink is glued in very tightly, expect the removal and prep work alone to take a full day.

Can I reuse my old garbage disposal?

Yes, you can often reuse an older disposal if it is still working well. Make sure the mounting flange attached to the sink is compatible with your new sink drain opening. If the flange doesn’t fit the new drain opening size, you will need a new disposal mounting kit.

What is the difference between plumber’s putty and silicone caulk for sealing?

Plumber’s putty is soft and moldable, perfect for sealing drain hardware (like strainer baskets) because it never fully hardens, allowing for minor adjustments later. Silicone caulk is a waterproof adhesive that fully cures and hardens, making it the necessary sealant for kitchen sink rims where the sink meets the countertop to prevent water from getting underneath.

Do I need to call a plumber for the plumbing under sink connections?

If you are simply reconnecting standard drain pipes using slip nuts and standard faucet supply lines, most handy homeowners can manage it. However, if you encounter rusted pipes, need to cut and thread new metal pipes, or deal with complicated P-trap configurations, calling a professional plumber is wise to prevent future leaks.

What if the new sink cutout is the wrong size?

If the new sink is significantly smaller than the old countertop opening, you will likely have a large gap. You cannot use a drop-in sink unless you have custom countertop material installed to cover the gap. If the new sink is larger, you will need a professional countertop company to cut the opening larger, which is often necessary when switching to a larger undermount sink replacement.