Turn off both the hot and cold water supply valves located under the sink. They should turn clockwise to close. Then turn the faucet on and let it run until water stops flowing — this relieves line pressure and drains residual water from the supply tubes. Place your bucket under the P-trap before continuing.

Empty the sink cabinet completely. Crawl in with a flashlight and disconnect the supply lines (hot and cold) from the shutoff valves using adjustable pliers. Have your bucket ready — residual water will drain out. Unscrew the P-trap slip-joint nuts and lower the trap into the bucket to catch trapped water.

If there's a garbage disposal, unplug it and disconnect it from the drain before removing the sink. Disposals attach via a mounting ring on the drain — rotate counterclockwise to release.

Drop-in: Locate the mounting clips securing the sink rim from underneath. Use a screwdriver to loosen each clip and swing it away from the countertop. Then run your utility knife firmly around the entire perimeter of the sink rim to score through the old caulk or silicone seal.

Undermount: Remove any visible mounting hardware or brackets from the underside of the countertop. The sink is likely bonded with silicone and possibly construction adhesive — score around the seam where the sink rim meets the underside of the counter using your utility knife. Have a helper support the sink from below before fully breaking the bond.

Drop-in: With a helper supporting from below, push up on the sink from underneath to break it free, then lift it out and set it aside. Cast iron sinks are extremely heavy — have two strong helpers and a clear path before lifting.

Undermount: Have your helper hold the sink from below as you fully score and release it. Lower it carefully — do not let it drop. Stone countertop edges can chip if the sink swings against them.

Once removed, use a putty knife to scrape all old silicone, caulk, and adhesive residue from the countertop opening. Clean the surface with denatured alcohol and let it dry completely before installing the new sink. Silicone will not bond well to dirty, oily, or damp surfaces.

With the new sink sitting upside down or face-up on your work surface, install the faucet per the manufacturer's directions. Thread the supply line tailpieces down through the faucet holes and tighten the mounting nut from below using your basin wrench. Attach any faucet deck plate if applicable.

Clean the sink thoroughly before installation — especially stainless steel sinks, which arrive from the factory with a strong metallic odor and may have protective coating residue. Scrub with dish soap outdoors before bringing it inside.

Two critical mistakes to avoid at this stage: (1) forgetting to clean the sink before installing, and (2) forgetting to install the faucet before the sink goes in. Both force difficult under-cabinet work later.

Run a continuous bead of 100% kitchen-grade silicone sealant around the perimeter of the countertop opening — apply it to the countertop rim, not the sink rim, so you can see where you're placing it. The bead should be steady and even — about ¼" in diameter.

Carefully lower the sink into the opening, aligning it precisely. Press firmly and evenly around the rim to spread the silicone. Check that the rim is flush and seated all the way around before the silicone begins to skin over.

Crawl under the sink and locate the mounting clip slots in the underside of the sink rim. Insert the provided clips, then use a screwdriver to tighten them against the underside of the countertop. Tighten in a star or alternating pattern — don't tighten one side fully before moving to the other, or the sink can shift out of alignment.

Wipe away any silicone that squeezed out around the rim perimeter with a damp cloth before it cures. Allow at least 24 hours before use for the silicone to fully cure.

Install faucet and drain onto the sink first (see drop-in Step 5). Then, clean the underside of the countertop and the sink rim thoroughly with denatured alcohol. Let both surfaces dry completely — silicone and construction adhesive require a clean, dry, oil-free surface to bond properly.

Hold the sink up to the underside of the countertop and use painter's tape to mark exactly where the sink rim edge meets the counter. Mark the clip locations at each corner and every 8–10" along the sides. These marks are your guide — once adhesive is applied, you must position the sink precisely on the first attempt.

Apply a continuous bead of 100% silicone sealant around the entire rim of the sink — not plumber's putty, which does not bond well to stone or composite countertop surfaces. For heavier sinks (stone composite or cast iron), also apply construction adhesive (such as SikaFlex-11FC) as the primary structural bond; silicone serves as the waterproof secondary seal.

Work quickly — construction adhesive and silicone begin setting within 10–15 minutes. Have your helper ready to position the sink immediately after application.

With your helper supporting the sink from below, lift it into position against the underside of the counter. Align with your tape marks. Press the rim firmly against the countertop surface to spread the adhesive evenly.

Install the mounting clips at each marked location while your helper holds the sink in position. Tighten clips gradually, alternating sides — never fully tighten one side before starting the other. Uneven tightening pulls the sink out of alignment and can stress the countertop edge.

Place foam blocks or wooden shims underneath the sink to provide support while the adhesive cures — the clips alone may not hold a heavy sink against gravity during the cure window.

Wipe away any excess silicone that squeezed out from the rim immediately with a damp cloth before it cures. Once cured, trimming away hardened silicone is much harder and risks marring the counter surface.

Drop-in sinks: Apply a rope of plumber's putty around the underside of the drain strainer flange before inserting it into the drain opening. Press it firmly down, then from below thread on the rubber gasket, friction washer, and lock nut. Tighten the lock nut with a basin wrench — hand-tight plus a quarter turn. Do not overtighten — this can crack porcelain or composite sinks.

Undermount sinks: Use silicone sealant around the drain flange instead of plumber's putty. Putty can stain or react with some undermount sink materials. Thread and tighten the drain assembly from below as above.

Once the strainer is set, thread on the drain tail pipe (the straight section that extends down into the cabinet). Hand-tighten only at this stage — you'll align it properly when connecting the P-trap.

The P-trap is the curved drain section that retains water to block sewer gases from entering the kitchen. Slide the new P-trap onto the drain tail pipe and align the outlet with the drain stub-out in the wall. Connect using slip-joint nuts — hand-tighten only, then a quarter to half turn more with pliers.

Replace the P-trap if it is old, corroded, or has been leaking. New P-trap kits are inexpensive and available at any hardware store. Never reuse a cracked or mineral-encrusted trap — it will leak.

If the tail pipe is too long to align with the wall stub-out, trim it with a hacksaw. If it's too short, use a trap arm extension. The P-trap leg should be slightly lower than the outlet to the wall so water drains by gravity.

Thread the new flexible braided supply lines onto the faucet tailpieces (if not already attached). Most modern supply lines have a 3/8" compression fitting at the valve end and a 1/2" or 7/16" connection at the faucet end — verify sizes match your faucet and valves before purchasing.

Hand-tighten the supply line connections to the shutoff valves. Do not overtighten — the rubber washer inside the connection creates the seal. Snug plus a quarter turn with pliers is sufficient. Overtightening crushes the washer and causes leaks.

Hot water connects to the left faucet handle inlet, cold to the right — standard North American plumbing convention. Confirm by checking your supply line labels.

Remove the aerator from the faucet spout before turning water on. Installation debris — pipe scale, metal flakes, and sediment — can be flushed through the lines when water first runs. Catching this in the aerator rather than letting it clog inside will save you from future low-flow issues.

Slowly open the hot and cold shutoff valves. Let water run for at least two to three minutes, checking every connection point as you go.

Places to inspect carefully:

• →Both supply line connections at the shutoff valves
• →Both supply line connections at the faucet tailpieces
• →Around the faucet base where it meets the sink deck
• →Around the drain strainer flange (top and underside)
• →All P-trap slip-joint connections
• →Around the drain outlet at the wall stub-out

Run water, fill the sink partially, and then drain it — watch the P-trap during drain flow, as drain leaks only appear under active flow pressure. Tighten any fitting that shows moisture by a quarter turn at a time. Reinstall the aerator once testing is complete.