How to Install a Kitchen Faucet
Updated February 20, 2026
Remove an old kitchen faucet and install a new one from start to finish -- disconnect supply lines, pull the old faucet, mount the new one, and connect everything leak-free.
Overview
A new kitchen faucet is one of the most satisfying upgrades you can do -- instant visual improvement and no more dealing with years of mineral buildup and dripping valves. The whole job takes 1-2 hours with no special plumbing skills. The hardest part is working in the cramped space under the sink, which is why a basin wrench is essential. Replacing an existing faucet? Disconnect, clean, install in the same holes. Changing styles (say, three-hole centerset to single-hole)? You will need a deck plate to cover the extra holes. This guide covers the full process including the supply line connections that trip most people up.
What You'll Need
Safety First
- Shut off both hot and cold supply valves under the sink before disconnecting anything. Open the faucet to bleed pressure. If the valves do not close fully (common with old gate valves), shut off the main.
- Bucket under the connections before you disconnect. Even with the valves off, water trapped in the lines will pour out.
- Clear everything out of the cabinet first. You need room to maneuver and a clear path for tools. A headlamp frees up both hands -- you will need them.
Step-by-Step Instructions
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Disconnect the Old Faucet Supply Lines and Sprayer
Valves off, faucet open to drain, bucket in position. Disconnect the supply lines from the shut-off valves first (lower connections, adjustable wrench). Then disconnect from the faucet tailpieces above -- this is where you need the basin wrench because of the tight space. Side sprayer? Disconnect its hose from the diverter fitting. Let everything drain into the bucket.
Tip: Corroded supply line nuts that will not budge? Spray with penetrating oil (WD-40 or PB Blaster) and wait 15 minutes. Still stuck? Cut the lines -- you should be replacing them with new braided stainless steel anyway. -
Remove the Old Faucet
From below, find the mounting nuts on the faucet tailpieces or mounting studs. Basin wrench, counterclockwise, off they come. Once the nuts are out, the faucet lifts straight up from above -- you may need to rock it if old putty or silicone is holding on. Clean the sink surface thoroughly: scrape off old putty, silicone, and mineral buildup with a plastic putty knife, then clean with rubbing alcohol or lime remover.
Tip: A basin wrench ($10-15) is not optional for this job. It is a T-shaped tool with a pivoting jaw that reaches into the narrow space behind the sink where nothing else fits. Trying to do this without one is an exercise in frustration. -
Prepare and Mount the New Faucet
Read the instructions -- every brand has different mounting hardware. Some faucets need supply lines or sprayer hoses attached before they go into the sink. If the faucet needs a putty or gasket seal: plumber's putty around the base plate for metal or porcelain sinks, or the rubber gasket included with most modern faucets. Drop the faucet into the holes from above. From below, thread the mounting nuts onto the tailpieces or studs and tighten with the basin wrench. Check that the faucet is centered and straight before you fully tighten.
Warning: Granite, quartz, or marble countertop? Use the gasket or silicone only -- never plumber's putty. Putty stains natural stone permanently. Some stone sealers also react with putty chemicals. -
Connect the Supply Lines
Connect supply lines to the faucet tailpieces first (upper connection, easier before the lines are connected below). Hand-tighten each one, then a quarter turn with a wrench -- the rubber or nylon washer creates the seal, not brute force. Then connect the lower ends to the shut-off valves. Hot is left, cold is right (facing the sink). Same approach: hand-tight plus a quarter turn. Pull-down or pull-out sprayer? Connect the hose per the manufacturer's instructions -- usually a quick-connect fitting that snaps together.
Tip: Always use new supply lines with a new faucet. Reusing old ones is the number one cause of leaks after installation. Braided stainless steel ($5-10 each) is the standard -- flexible, durable, and far more reliable than the cheap plastic or rubber lines that come with some faucets. -
Connect the Sprayer Hose and Weight (If Applicable)
Pull-down or pull-out sprayer? Route the hose down through the faucet body. Clip the counterweight (small metal cylinder) onto the hose about 6-8 inches below the faucet body -- that weight is what pulls the sprayer head back into the spout after use. Make sure the hose moves freely without kinking or catching on anything. Separate side sprayer (less common now)? Connect its hose to the diverter fitting on the faucet body.
Tip: Position the counterweight so the hose makes a smooth arc. Too low and the sprayer does not retract fully. Too high and it snaps back too hard. Six to eight inches below the spout exit is usually right. -
Test for Leaks and Verify Operation
Remove the aerator from the spout tip before the first run -- this prevents debris from clogging it. Turn on the shut-off valves slowly (hot first, then cold). Let water run for 30-60 seconds to flush debris from the new faucet and lines. While it runs, check every connection with a flashlight: both valve connections, both tailpiece connections, sprayer hose, and the faucet base. Tighten anything that drips a quarter turn. Reinstall the aerator. Test hot and cold separately, test sprayer retraction, and check under the sink again after 30 minutes of normal use.
Tip: Skipping the aerator removal before the first flush means construction debris and pipe shavings clog the screen immediately. Flush without the aerator first, then clean it and put it back.
Pro Tips
- Count your sink holes and measure hole spacing before buying a faucet. A single-hole faucet needs a deck plate on a three-hole sink (most quality faucets include one). See our faucet buying guide for matching.
- Photo the plumbing under the sink before you disconnect anything. Clear reference for how the supply lines route and connect, especially if the new faucet has a different configuration.
- Old gate valves under the sink? This is the perfect time to swap them for quarter-turn ball valves ($10-15 each). Water is already off, you are already down there -- 20 minutes now saves a separate repair later.
- Many modern faucets have pre-attached supply lines built into the body. These connect directly to the shut-off valves, eliminating separate lines and two connection points. Fewer connections means fewer potential leaks.
- After installation, run full hot for 2 minutes, then full cold for 2 minutes. This purges air from the lines and verifies both supply connections are fully open. Sputtering is just trapped air, not a problem.
When to Call a Pro
This is standard DIY. Call a plumber if the shut-off valves will not close (need replacing before you can work), if sink holes need drilling in granite or quartz, if the old faucet is corroded so badly the mounting nuts have to be cut off, or if you are going with a wall-mount faucet that needs in-wall plumbing changes.