A plumber will charge $150 to $350 to swap a kitchen faucet, and the job itself is often less than an hour of work with tools you already own. Kitchen sink faucet installation intimidates people mainly because it happens in the cramped, dark cabinet under the sink, but the actual steps are simple and forgiving. Master the sequence once and you’ll never pay for a faucet swap again.
Part of our Kitchen Remodeling guide — explore the full guide →
Tools and Parts You’ll Need
Gather everything before you crawl under the sink. Most installs need only a basin wrench, an adjustable wrench, plumber’s tape, a bucket, and a flashlight or headlamp. A basin wrench is the hero tool here; its swiveling head reaches the mounting nuts hidden behind the sink where a regular wrench can’t fit.
Check that your new faucet’s connection type matches your existing supply lines. Buy new braided stainless supply lines while you’re at it; they cost a few dollars and prevent a repeat trip under the cabinet if the old ones are stiff or corroded.
Step One: Shut Off and Drain
Turn off both hot and cold shutoff valves under the sink, usually by turning them clockwise until snug. Open the faucet to release pressure and let the lines drain into your bucket. If the shutoff valves are stuck or don’t fully close, shut off the home’s main water supply instead.
Put a towel and the bucket in the cabinet to catch the water that always drips out when you disconnect the lines. Clearing everything out of the cabinet first gives you room to work and a flat spot for your tools.
Step Two: Remove the Old Faucet
Disconnect the supply lines from the faucet tailpieces with your wrench, then use the basin wrench to loosen the mounting nuts holding the faucet to the sink. If there’s a sprayer or soap dispenser, disconnect those too. With the nuts off, lift the old faucet out from the top.
Scrape away the old plumber’s putty or gasket residue and clean the mounting holes thoroughly. A clean, dry deck is essential for the new faucet’s gasket to seal properly and for a tidy final look.
Step Three: Mount the New Faucet
Most modern faucets install from above with a deck plate or gasket that seals without putty, though some still call for a bead of plumber’s putty or silicone under the base. Feed the faucet’s supply lines and any hose down through the mounting hole, seat the faucet square with the sink’s back edge, and hand-thread the mounting hardware from below.
Tighten the mounting nut with the basin wrench, checking from above that the faucet stays straight and doesn’t rotate. Snug is the goal; overtightening can crack a thin sink deck or a plastic mounting nut.
Step Four: Connect the Water Lines
Wrap the threaded connections with two or three turns of plumber’s tape, then attach the supply lines: hot to the left, cold to the right. Hand-tighten first, then give each connection a quarter to half turn with a wrench. Don’t crank them; braided lines seal with a rubber washer and overtightening can damage it.
- Hot line: left inlet, from the hot shutoff valve
- Cold line: right inlet, from the cold shutoff valve
- Pull-down hose: connect and attach the counterweight if included
Step Five: Test for Leaks
Remove the aerator from the faucet spout first so any debris in the lines flushes out instead of clogging it. Slowly reopen both shutoff valves and turn the faucet on, running hot and cold and the sprayer. With a flashlight, watch every connection under the sink for drips while the water runs and again after you shut it off.
If you spot a leak, snug that fitting another quarter turn. Reinstall the aerator once the water runs clear, and run the faucet another minute to confirm everything is dry.
Common Mistakes to Avoid
The most frequent errors are cross-threading a supply-line nut, forgetting the plumber’s tape, and overtightening plastic fittings until they crack. Take a moment to start every threaded connection by hand so it can’t cross-thread, and stop tightening the instant a fitting feels firm.
Handling a Pull-Down or Sprayer Faucet
Pull-down and pull-out faucets add one extra step: the spray hose and its counterweight. Feed the hose through the faucet body before you mount it, then clip the counterweight onto the hose under the cabinet according to the diagram, since it’s what retracts the sprayer back into the spout. If the sprayer doesn’t return fully after install, the counterweight is usually in the wrong spot on the hose or is snagging on a supply line.
Route the hose so it hangs freely with nothing blocking its travel. A hose that catches on a shutoff valve or the drain trap is the most common complaint with these faucets, and it’s a two-minute fix once you spot the obstruction.
Knowing When to Call a Pro
Most faucet swaps are firmly in DIY territory, but a few situations warrant a plumber. If your shutoff valves are corroded and won’t close, if the old supply lines are soldered copper with no shutoffs, or if you discover a cracked sink or damaged countertop under the old faucet, those are worth a professional’s hands. Replacing a failed shutoff valve, in particular, means working on the pressurized supply line and is better left to someone equipped for it.
For a standard swap on functioning shutoffs, though, there’s no reason to pay for labor.
Also double-check that hot and cold aren’t reversed before you close up. Handled patiently, a full kitchen sink faucet installation takes most homeowners under an hour and saves the entire plumber’s service fee, all with a couple of wrenches and a roll of plumber’s tape.
