How to Install a Kitchen Sink: Complete Step-by-Step Guide

So you’re staring at that old, stained kitchen sink thinking it’s time for an upgrade. Or maybe you’re in the middle of a kitchen remodel and the sink installation is your next challenge. Either way, you’re probably wondering if this is something you can actually handle yourself. Let’s walk through exactly how to get this done.

What You’ll Need Before You Start

Before you disconnect anything, let’s make sure you have everything on hand. Nothing worse than having your kitchen torn apart and realizing you need to make a hardware store run.

Essential Tools:

• Adjustable wrench (or better yet, a basin wrench)
• Channel lock pliers
• Plumber’s putty or silicone caulk
• Bucket (for catching water)
• Towels (more than you think you need)
• Screwdriver (Phillips and flathead)
• Utility knife

Materials You’ll Need:

• Your new sink (obviously)
• New sink strainer(s) if not included
• Drain assembly kit if needed
• Supply lines if yours are old
• Teflon tape
• Mounting clips (usually come with the sink)

Nice-to-Have Items:

• Headlamp or flashlight (you’ll be under that cabinet)
• Knee pads or old cushion
• Penetrating oil (for stubborn connections)
• New shut-off valves (if yours are ancient)

Quick Safety Check Before You Begin

Look, kitchen sink installation isn’t dangerous like electrical work, but there are a few things to keep in mind. First, you’ll be working with water connections, so know where your main water shut-off is, just in case. Most of the time, you’ll just use the shut-off valves under the sink, but if those fail (and old ones sometimes do), you need a backup plan.

Clear everything out from under your sink cabinet. I mean everything. You need room to work, and trust me, you’ll be spending quality time down there. Put down some towels to cushion your back and catch any drips.

If you’re installing a heavier sink like cast iron or composite, get help. These sinks can weigh 50+ pounds, and trying to position them solo while lying on your back is a recipe for disaster.

How to Remove Your Old Kitchen Sink

Alright, let’s get that old sink out of there. This is usually the messiest part, so let’s do it right.

Step 1: Turn off the water supply

Locate the hot and cold shut-off valves under your sink and turn them clockwise until they stop. Turn on the faucet to release pressure and verify the water is off. No water coming out? Perfect. Still getting water? Your shut-off valves might need replacing (common in older homes), or you’ll need to shut off the main water supply.

Step 2: Disconnect the supply lines

Place your bucket under the connections. Using your wrench, disconnect the supply lines from the shut-off valves. Water will drip out. This is normal. Let it drain into your bucket. These connections can be tight, especially if they’re old. If they won’t budge, try some penetrating oil and let it sit for 10 minutes.

Step 3: Disconnect the drain

This is where things get a bit messy. Loosen the slip nuts connecting your P-trap to the sink drain and wall drain. Have that bucket ready because there’s definitely water in there, and it might not smell great. Once disconnected, remove the entire P-trap assembly. Stuff a rag in the wall drain pipe to prevent sewer gases from coming up.

Step 4: Detach the sink from the countertop

If you have a drop-in sink, look for clips underneath holding it in place. Unscrew these clips and set them aside (you might reuse them). For undermount sinks, there are usually brackets or clips attached to the underside of the counter. Remove these carefully.

Run a utility knife along the edge where the sink meets the counter to break the caulk seal. This might take some effort if the caulk is old and stubborn.

Step 5: Remove the sink

For drop-in sinks, you should be able to lift it straight up. It might be stuck from years of caulk and grime, so gently work it loose. Undermount sinks need to be supported from below as you remove the last clips. This is definitely a two-person job.

Once out, clean up any old caulk or putty from the countertop using a plastic scraper. Don’t use metal on laminate countertops as it can scratch.

Installing Your New Kitchen Sink

Now, for the fun part; putting in your new sink. The process varies slightly depending on your sink type, but here’s the general approach.

For Drop-In (Top-Mount) Sinks

Step 1: Check the fit

Set your new sink in the opening to make sure it fits properly. It should sit flat with even reveals on all sides. If your new sink is smaller than the old one, you might have a problem. If it’s slightly larger, you might need to trim the opening (laminate only — don’t try this with granite or quartz).

Step 2: Install the faucet and strainer

This is so much easier to do now than after the sink is installed. Follow your faucet’s instructions, but generally, you’ll feed the supply lines through the hole, position the faucet, and tighten the mounting nuts from below. Hand-tight plus a quarter turn is usually enough. Don’t overdo it!

For the strainer, roll plumber’s putty into a rope and place it around the drain opening underside. Press the strainer into place from above, then from below add the rubber gasket, cardboard friction ring, and mounting nut. Tighten until the putty squeezes out, then clean the excess.

Step 3: Apply sealant

Run a continuous bead of silicone caulk or plumber’s putty around the countertop opening edge. Don’t skimp here, as a good seal prevents water damage to your cabinet.

Step 4: Set the sink

Carefully lower the sink into place. Press down evenly to spread the sealant. You should see it squeeze out slightly all around. If your sink came with clips, install them now from below, spacing them evenly. Tighten the clips gradually, alternating sides to ensure even pressure.

Step 5: Clean excess sealant

Wipe away squeezed-out sealant with a damp cloth. For silicone, you want to do this right away. For plumber’s putty, you can wait until it firms up a bit.

For Undermount Sinks

Undermount installation is trickier and varies significantly based on your countertop material. For solid surfaces like granite or quartz, you’ll need special clips and probably professional help for cutting and polishing. But if you’re replacing an existing undermount with the same size, here’s the process:

Step 1: Prepare the sink

Install your faucet and strainer while the sink is accessible. Apply a bead of silicone adhesive around the sink rim according to manufacturer instructions.

Step 2: Position and support

You’ll need help here. Have someone hold the sink in position from below while you check alignment from above. The sink should be centered and level. Use a 2×4 brace system to hold the sink in place temporarily.

Step 3: Secure the sink

Install the mounting clips according to your countertop type. For stone counters, these usually involve brackets that attach to threaded posts epoxied into the stone. For wood or laminate, you might use clips that screw into the underside. Follow your specific sink’s instructions carefully.

Step 4: Let it cure

Keep the support braces in place for at least 24 hours while the adhesive cures. Don’t connect plumbing yet. Let everything set properly.

Connecting the Plumbing

With your sink securely mounted, it’s time to get the water flowing again.

Step 1: Install the drain assembly

Connect your P-trap to the sink drain tailpiece. Use slip-joint washers at each connection and hand-tighten the nuts. Then give them another quarter turn with pliers. Don’t overtighten as you can crack the plastic. Align everything so water flows smoothly toward the wall drain.

Remove the rag from the wall drain and connect the P-trap. Make sure all connections are secure but not overtightened.

Step 2: Connect supply lines

If your old supply lines looked crusty or are more than 10 years old, replace them. New braided stainless steel lines cost about $10 each and give you peace of mind. Connect them to your shut-off valves first (use Teflon tape on the threads), then to your faucet connections. Again, hand-tight plus a quarter turn is plenty.

Step 3: Check for leaks

Remove the aerator from your faucet (debris might come through the lines initially). Turn on the shut-off valves slowly. Check all connections for leaks. Turn on the faucet and let it run for a minute. Check under the sink again. Sometimes leaks only show up under pressure.

Look particularly at the strainer connection and P-trap joints. If you see any drips, tighten the connection slightly. Still leaking? You might need to reseat the connection with fresh putty or tape.

Step 4: Test everything

Fill the sink with water and then drain it, watching for leaks at the strainer and drain connections. Run the garbage disposal if you have one. Make sure both hot and cold water work properly. Check that the sink doesn’t move or shift when you press on it.

How to Install a Kitchen Sink Faucet

Since you’re often doing both at once, let’s cover faucet installation specifically. Even if you’re keeping your old sink, a new faucet can transform your kitchen.

Preparing for faucet installation

Preparing for faucet installation starts with choosing the right faucet for your sink configuration. Count your holes, most sinks have 1, 3, or 4 holes. You can use fewer holes than you have (cover extras with deck plates or soap dispensers), but you can’t use more without drilling.

Removing the old faucet

Removing the old faucet follows the same initial steps as sink removal — turn off water, disconnect supply lines. Then loosen the mounting nuts holding the faucet to the sink. These can be incredibly stubborn after years of corrosion. A basin wrench is worth its weight in gold here, letting you reach those nuts in tight spaces. Sometimes you need to cut old supply lines to get access.

Installing the new faucet

Installing the new faucet is easier on a new sink, but here’s the process either way: Clean the mounting surface thoroughly. If you have a gasket, place it on the sink. If not, use plumber’s putty. Feed the faucet lines through the appropriate holes. From below, thread on the mounting hardware. Center the faucet and tighten evenly.

For pull-down spray faucets, connect the spray hose to the faucet body (usually a quick-connect fitting). Make sure the weight is properly positioned on the hose so it retracts smoothly. Connect your supply lines, using Teflon tape on threads.

The key to a good faucet installation is taking your time with the mounting. A wobbly faucet will loosen over time and cause leaks. Make sure it’s centered, straight, and firmly mounted before connecting water lines.

Installing a New Kitchen Sink in a New Counter

If you’re installing a sink in a brand new countertop or doing a full remodel, the process has some additional considerations.

First, you need to cut the opening (unless you bought a custom counter with pre-cut holes). For laminate countertops, use the template that came with your sink. Tape it in position, ensuring it’s square to the cabinet face and centered. Drill starter holes in the corners, then cut with a jigsaw using a fine-tooth blade. Go slow to prevent chipping.

For butcher block or wood counters, the process is similar but seal all cut edges with polyurethane to prevent water damage. Multiple coats are better than one thick coat.

Stone countertops (granite, quartz, marble) require professional cutting with specialized tools. Don’t attempt this yourself unless you have experience and proper equipment. The cost of ruining a granite slab far exceeds professional installation fees.

New installations also mean you’re likely running new drain lines. Make sure your drain alignment matches your sink position. The drain should connect to your P-trap without excessive angles or strain. If it doesn’t line up, you might need to modify the drain pipe positioning (this usually requires a plumber, especially if you’re not comfortable with pipe work.)

Common Mistakes and How to Avoid Them

• Forgetting to turn off the water sounds obvious, but you’d be surprised how many people skip this step. Always turn off the water first, then verify it’s off by running the faucet.
• Over-tightening connections is probably the most common mistake. Plumbing connections need to be snug, not gorilla-tight. Over-tightening cracks plastic fittings, strips threads, and deforms gaskets causing leaks. Remember: hand-tight plus a quarter turn for most connections.
• Wrong sink size happens more than you’d think. People assume their new sink will fit the existing hole. Always measure the actual opening, not just the old sink. Measure twice, buy once. 

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Other Things You Need To Know When Remodeling Your Kitchen

Cabinets

The kitchen cabinets are arguably the costliest (taking about 30% of your total budget) and most important consideration in your kitchen remodel. If you’ll be using your current layout, and simply updating the look of your space, refinishing or painting your cabinets can save you a great deal of money. It’s also something you can likely do yourself with just a bit of homework and preparation. You can find plenty of helpful advice online, like this article from This Old House. If you’ll be expanding your space or changing the layout, consider a combination of new and existing cabinets. Maybe you’ll be adding a new kitchen island. If so, you may be able to paint or refinish the cabinets around the perimeter of your kitchen and install complementary cabinets for the kitchen island.

Countertops

The options available for countertops are virtually unlimited. There’s stone, tile, concrete, quartz, marble, butcher block, stainless steel, granite, Formica and Corian just to name the most popular. While not the most expensive part of a kitchen remodel, the countertop can certainly take a bite out of your budget, depending on the material you choose.  As with the cabinets, if you’re simply adding a kitchen island, you may be able to keep your existing countertops on the perimeter of the room and add a complementary countertop on the island.

Flooring

Just like countertops, there are many options available in kitchen flooring. Beyond hardwood, ceramic tile and porcelain tile, today’s luxury vinyl tile offers a great combination of both affordability and durability. And this is not your mother’s vinyl tile. Modern LVT can be made to look so much like real hardwood planks or porcelain tiles that they can fool even the most critical eye. Plus, they are tough enough to stand up to the most active family’s wear and tear.

Appliances

Take the location of each of these into consideration. Do you need to move them in order to improve work or traffic flow? Will a larger appliance mean less space, etc.? Will it fit? Can you work with what you’ve got? If you can avoid purchasing new appliances, you’ll save a good amount of money that can be used in other areas of your budget. But if your appliances aren’t working well for your family, consider upgrading. You may be able to save a bit of money on a new, larger, more modern fridge or stove by shopping floor models or “dinged” or “scratched” products at local appliance stores. Some appliances are slightly damaged in shipping to stores and then are sold at a discount. And once they’re installed, most of these surface imperfections aren’t even visible.

Plumbing Upgrades

Depending on the extent of your kitchen remodel, it may require a bit of plumbing work. The cost will depend on the upgrades you’re making. If you’re moving appliances or replacing older piping, you’ll want to budget anywhere from $200 – $1000 for labor. Remember to hire a professional plumber! Check the Better Business Bureau and sites such as Home Advisor for recommendations. (Maplewood Plumbing and Sewer has more than 30 years of experience, has an A+ BBB rating and is top rated by Home Advisor!)

Electrical Wiring

A kitchen remodel typically results in new lighting. Whether you’re adding task or recessed lighting, electrical wiring will need to be run. You can modernize your kitchen simply by adding SUB outlets that make it easy to charge smart phones and tablets. As with plumbing, be sure to hire a licensed electrician for all your wiring needs. Angie’s List is a great resource for finding the right contractors. (Maplewood Plumbing is proud to be an Angie’s List Super Service Award winner since 2009!)

Finishing Touches

While there are standard design styles to choose from: Traditional, Contemporary, Transitional, Rustic, etc., you don’t have to follow any specific formula to create a beautiful kitchen. Create a space unique to your family by adding personal touches. For example, if your family is proud of its generations of great bakers, include a custom shelf to house your favorite recipe books or frame a favorite recipe written in a family member’s own handwriting. Adding these personal touches to your new kitchen will make it feel uniquely your own.

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Reach out to our team for more tips, tricks and insider-info on kitchen remodeling.  Maplewood Plumbing & Sewer has been taking care of St. Louis’ kitchen plumbing needs since 1985. We have extensive experience replacing fixtures, installing ice maker lines and garbage disposals, moving gas lines and many other kitchen remodeling tasks. 

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Frequently Asked Questions

How do I install a kitchen sink drain?

Installing a kitchen sink drain starts with applying plumber’s putty around the drain flange from underneath. Insert the drain basket from above, pressing firmly to seat it. From below, slide on the rubber gasket, then the cardboard friction ring, and finally the locknut. Tighten the locknut while holding the drain basket steady from above (a friend helps here).

The key is getting the putty seal right. Use enough to create a complete ring, but not so much that cleanup is impossible. Tighten until putty just squeezes out evenly around the drain in the sink basin. Connect the tailpiece to the drain basket, then connect your P-trap. Make sure everything slopes slightly toward the wall drain for proper drainage. Test with water before calling it done.

How long does it take to install a kitchen sink?

For an experienced DIYer replacing a similar sink, expect 2-3 hours. First-timers should budget 4-5 hours to work carefully and avoid mistakes. The timeline breaks down roughly like this: removing the old sink takes 30-45 minutes, preparing the area and new sink takes 30 minutes, installing the new sink takes 45-60 minutes, and reconnecting plumbing takes 45-60 minutes.

Add extra time if you’re also replacing the faucet (add 1 hour), dealing with corroded connections (add 30-60 minutes), or modifying cabinets for a farmhouse sink (add 2-3 hours). Undermount sinks need 24 hours for adhesive to cure before connecting plumbing. 

How to install a kitchen sink faucet with a sprayer?

Installing a faucet with sprayer follows the basic faucet installation but with extra steps for the spray hose. First, mount the faucet base as normal. Before tightening completely, feed the spray hose through the faucet body from below, it’s usually a quick-connect fitting that clicks into place. Make sure the hose moves freely without kinking.

Attach the spray weight to the hose at the specified position (usually 10-12 inches from the spray head). This weight makes the sprayer retract properly. Test the sprayer’s movement before finalizing the faucet mounting — it should pull out smoothly and retract completely. If using a separate sprayer (not pull-down), it installs in its own hole with a mounting nut below. Connect its hose to the dedicated port on the faucet body.

Can I install a kitchen sink myself?

Drop-in sinks are the most DIY-friendly, requiring just basic tools and patience. You’ll need to be comfortable working in tight spaces (under the cabinet) and following instructions carefully. The plumbing connections are usually straightforward compression or threaded fittings.

However, some situations need professional help: undermount sinks in stone counters, extensive plumbing modifications, or if you discover damaged pipes or valves during removal. If you’re not comfortable with any step, calling a plumber for a few hundred dollars beats causing thousands in water damage. Most importantly, know your limits – there’s no shame in calling a pro for complex installations.

What’s the most common kitchen sink size?

The most common kitchen sink size is 33 x 22 inches for a standard double bowl. This fits in a 36-inch sink base cabinet, which is standard in most kitchens. Single bowl sinks commonly measure 25 x 22 or 30 x 22 inches. Depth typically ranges from 8 to 10 inches, with 9 inches being most common.

When replacing a sink, don’t assume standard sizing. Always measure your actual cabinet and cutout. Cabinet sizes can vary, especially in older homes or custom kitchens. Remember that the sink size isn’t the same as the cutout size. Check the specification sheet for exact cutout dimensions. Also consider your counter depth; standard is 25 inches, but some are 24 or 26 inches, affecting which sinks fit.