This guide walks through replacing a kitchen faucet — shutting off the water supply, disconnecting and removing the old faucet, preparing the sink deck, installing the new faucet and deck plate, connecting new supply lines, and confirming a leak-free installation. The job is accessible to a homeowner with basic plumbing experience and the right tools. The hardest physical part is working in a cramped space under the sink; the most common errors involve supply line thread sizing and forgetting to tighten the mounting nut before connecting supply lines.
Most modern kitchen faucets are single-hole pull-out or pull-down models that fit a 1-3/8-inch hole. Three-hole configurations (widespread with separate hot, cold, and spout holes) are still common in older kitchens and require different hardware. The steps below note where the process differs for three-hole versus single-hole configurations.
Time: 1–2 hours. Cost: $80–$400 for the faucet; $10–$25 for new braided stainless supply lines. Difficulty: Intermediate. Permit required: No. Turn off water before starting: Yes — mandatory.
What You Will Need
Tools
Adjustable basin wrench (essential for reaching mounting nuts under the sink deck)
Adjustable pliers or slip-joint pliers
Bucket (1-gallon minimum) for residual water in lines
Flashlight or headlamp
Channel-lock pliers
Plumber's putty or silicone sealant (if the faucet base does not include a gasket)
Tape measure
Rags or small towels (for drips)
Materials
New kitchen faucet matching the sink's hole configuration (single-hole or 3-hole)
Deck plate (escutcheon) if covering a 3-hole sink with a single-hole faucet — most faucets include this
New braided stainless supply lines — 3/8-inch female compression × 1/2-inch female IPS, 16-inch or 20-inch length (measure under your sink before buying; do not reuse old supply lines)
Plumber's tape (PTFE tape) — 2 wraps on all threaded connections
Step 1 — Shut Off the Water Supply
Locate the hot and cold shutoff valves under the kitchen sink — standard angle-stop valves on 3/8-inch compression fittings. Turn both valves fully clockwise (hand-tight). Open the faucet to bleed residual pressure and confirm water stops flowing within 30 seconds. If the valves do not fully stop the flow (old valves often fail to seat completely), turn off the main house shutoff. Place the bucket under the supply connections before disconnecting anything.
If the shutoff valves are so old they cannot be turned without risk of breaking, this is the time to also replace them — it adds 30 minutes to the job and prevents a call to an emergency plumber later. See kitchen repair guides for shutoff valve replacement.
Step 2 — Disconnect and Remove the Old Faucet
From under the sink, disconnect both supply lines from the faucet inlet shanks — use the basin wrench to reach the nuts if clearance is limited. Have the bucket positioned to catch residual water from both lines. Once supply lines are disconnected, locate the mounting nut(s) on the faucet body — for single-hole faucets, one large mounting nut; for three-hole models, mounting nuts on each component. Use the basin wrench to loosen and remove. From above, lift the old faucet body straight up and out of the sink deck.
Clean the sink deck thoroughly before installing the new faucet. Mineral deposits, old plumber's putty, and silicone residue should be scraped away with a plastic scraper and cleaned with white vinegar. A clean, dry sink deck ensures the new faucet's base gasket or putty seal works correctly.
Step 3 — Install the Deck Plate (Three-Hole Sinks Only)
If covering a three-hole sink with a single-hole faucet, a deck plate (escutcheon) covers the extra holes. Most faucets include a deck plate for this purpose. Apply plumber's putty or a bead of silicone to the underside perimeter of the deck plate, set it on the sink deck over the holes, and press firmly. From below, install the deck plate mounting hardware and tighten the nut until the putty or silicone squeezes out evenly around the perimeter. Wipe the excess with a damp cloth. Allow silicone to cure 30 minutes before proceeding if silicone was used instead of putty.
Step 4 — Feed the Faucet Inlet Lines Through the Hole
From above, insert the faucet body's inlet lines through the sink deck hole. If the faucet has a base gasket, the gasket goes between the faucet base and the sink deck — no additional putty or sealant is needed. If the faucet has no gasket, apply a 3/8-inch rope of plumber's putty around the underside perimeter of the faucet base before inserting.
Step 5 — Secure the Mounting Nut
From under the sink, slide the mounting hardware (usually a plastic nut or a metal bracket and nut) onto the faucet's mounting shank. Tighten with the basin wrench. This step is physically awkward — you will likely be lying on your back with your head under the sink cabinet. Tighten until the faucet body does not rotate when you turn the handle above. Do not overtorque on plastic mounting nuts, which crack. Metal mounting nuts can be tightened more firmly.
This is the step most often skipped or undertightened. A faucet that is not fully tightened at the mounting nut rotates every time the handle is operated, eventually breaking the supply line connections below.
Step 6 — Connect the Supply Lines
Install new braided stainless supply lines — never reuse old supply lines. The faucet end of each supply line connects to the faucet inlet shank; the valve end connects to the shutoff valve. Apply 2 wraps of PTFE plumber's tape to all male threaded connections before assembling. Finger-tighten, then tighten 1/4 to 1/2 turn further with channel-lock pliers. Do not overtighten braided stainless supply line fittings — the rubber washer inside the fitting provides the seal; overtightening distorts the washer and causes leaks.
Confirm correct hot/cold orientation before tightening fully — the hot supply connects to the left (red) inlet and the cold to the right (blue). Reversed connections cause the faucet to run backwards and require disassembly to correct.
Step 7 — Turn Water On Slowly and Check for Leaks
Slowly turn the hot shutoff valve counterclockwise 1/4 turn. Watch the supply line connections for drips. Wait 30 seconds. Turn the cold shutoff valve the same way. Wait again. Open the faucet handle and let water run for 60 seconds. Check all four connection points: hot supply line to shutoff valve, hot supply line to faucet inlet, cold supply line to shutoff valve, cold supply line to faucet inlet. Check the base of the faucet where it contacts the sink deck — if putty or silicone was used, no drip should appear.
Any drip at a threaded connection: shut the valve, dry the fitting, add PTFE tape to the male threads, and re-tighten. Any drip at the faucet base: the mounting nut is likely not fully tightened. A drip that appears at the supply line fitting body after 30 minutes typically indicates an overtightened fitting that cracked the ferrule — replace that supply line.
Step 8 — Install Handle Hardware and Test
Install any decorative handle caps or trim pieces per the manufacturer's instructions. Run hot and cold water separately to confirm the temperature response is correct and that no vibration or chatter occurs in the supply lines. If the lines chatter or vibrate, they are under tension from being routed at too tight a bend — gently reposition them to relieve the bend.
Common Mistakes
Not turning off the water before starting. Even with good intentions, forgetting this step first causes a flood under the sink.
Reusing old supply lines. Old rubber-core supply lines are a leak and flood risk. New lines cost $10–$15 and the risk is not worth the savings.
Under-tightening the mounting nut. A loose faucet rotates at the base every time the handle is turned, eventually breaking the supply connections below.
Reversed hot and cold connections. Check the inlet labeling on the faucet body before connecting.
Overtightening supply line fittings. The rubber washer inside the fitting provides the seal — overtightening distorts it and causes the leak it was meant to prevent.
Not applying PTFE tape to male threaded connections. IPS threads are not self-sealing. Two wraps of PTFE tape on every male thread is mandatory.
Faucet Types and Selection Criteria
Kitchen faucet selection involves balancing hole count, handle configuration, spout reach, finish, and internal valve type. Each variable affects the installation process and the long-term ownership experience.
Single-Hole vs. Three-Hole Configurations
A single-hole faucet combines the spout and handle(s) into one deck plate that mounts through a single sink cutout. Three-hole configurations use separate deck holes for left handle, spout, and right handle (or sprayer). Most modern faucets ship with a deck plate that can cover a three-hole sink even when the faucet itself only requires one hole — this allows a single-hole faucet to replace a three-hole installation without sink modification. Confirm the hole count on the existing sink before purchase. Drilling additional holes in a granite or quartz sink requires a diamond-core drill bit and is a professional job.
Pull-Down vs. Pull-Out Sprayer Faucets
Pull-down sprayers hang vertically and retract from above the spout arch. They offer a high arc that improves clearance for filling tall pots. The hose length is typically 68–80 inches, providing good reach into a standard double-basin sink. Pull-out sprayers extend horizontally from the spout and retract forward. They work better in installations where overhead cabinet clearance is limited — a pull-down faucet's high arch requires at least 20 inches of clearance to the underside of the cabinet directly above. Measure cabinet height before selecting faucet style.
Ball, Cartridge, and Ceramic Disc Valves
The internal valve determines the operating feel, durability, and repair profile of the faucet. Ball valves use a hollow ball with ports that align with inlets and outlets as the handle rotates — a relatively simple mechanism that wears eventually and may develop drips after 5–8 years of heavy use. Cartridge valves use a replaceable plastic or brass cartridge with O-rings — highly reliable and repairable by replacing the $15–$40 cartridge. Ceramic disc valves use two mated ceramic discs — effectively no wear, tolerant of hard water, and the basis of most premium faucet lines. A single-lever faucet with a ceramic disc valve is the lowest-maintenance residential kitchen faucet available.
Faucet Finish and Long-Term Durability
Finish choice affects appearance and cleaning requirements. PVD (physical vapor deposition) finishes — including matte black PVD and brushed nickel PVD — are extremely durable and resistant to daily water contact and soap residue. Chrome finish is highly durable but shows water spots prominently. Brushed nickel (non-PVD) is moderately durable but can be scratched by abrasive cleaners. Oil-rubbed bronze is the most maintenance-intensive — it requires periodic re-oiling or waxing to prevent the bronze undertones from developing an uneven patina. Matte white and matte black finishes are fashionable but require weekly wiping to prevent mineral deposit accumulation in the texture.
Supply Line Selection and Sizing
Supply line selection is a safety-critical decision. The supply line is the single component that, if it fails, can flood the kitchen with hundreds of gallons of water in a short time.
Braided Stainless Steel Lines
Braided stainless steel supply lines have replaced rubber-core lines as the standard residential supply connection. The stainless braid provides puncture resistance and supports the internal rubber or polymer tube against pressure surges. Quality braided lines are rated to 500 psi burst pressure — far above the 60–80 psi of residential supply pressure. Purchase supply lines from established plumbing brands, not generic lines. The fitting geometry varies: 3/8-inch compression inlet, 1/2-inch FIP or 3/8-inch FIP faucet outlet — confirm both end types before purchase.
Line Length Selection
Supply line length should allow a gentle arc from the shutoff valve to the faucet inlet — not a tight curve and not so much excess that it kinks against the cabinet back. Standard under-sink depths are 20–24 inches. For most installations, 20-inch or 24-inch lines work correctly. Measure the run from the valve to the faucet inlet, add 8 inches of arc allowance, and purchase that length. An overly long line that must be coiled under the sink creates kink risk and is more difficult to service.
When to Upgrade Shutoff Valves
Quarter-turn ball shutoff valves (lever handle) are the current standard. If the shutoff valves under the sink are multi-turn gate or globe valves (round handle), this is a good opportunity to replace them. A corroded or partially-seized gate valve is a liability during any plumbing emergency. Replacing a shutoff valve requires turning off the house main — this is a 30-minute task that significantly improves the safety profile of the plumbing system. If the valve bodies are soldered copper, valve replacement should be done by a plumber. If the valves have compression fittings, a competent DIYer can complete the replacement.
Sink Deck and Mounting Surface Variations
The mounting approach differs depending on sink deck material and thickness.
Stainless Steel Sinks
Stainless steel sinks are the most forgiving for faucet mounting. The mounting hole is a clean punched circle. The mounting nut tightens directly against the underside of the stainless deck. Use the supplied rubber or silicone gasket at the faucet base — no additional sealant is needed. The mounting nut should be tightened until the faucet base has zero rotational play — do not overtighten, as deforming the stainless deck can cause the mounting hole to lose its geometry.
Cast Iron and Enameled Steel Sinks
Cast iron sinks have significant deck thickness (1/2–3/4 inch) that can prevent a short faucet shank from reaching the mounting hardware. Many faucets include shank extenders for thick-deck sinks — confirm this is in the hardware kit before installation. A missing shank extender results in the mounting nut threading on only the last few turns of the shank, leaving insufficient thread engagement for a secure mount.
Granite and Quartz Composite Sinks
Composite sink decks are thick (up to 1 inch) and require a shank extender in virtually every installation. The weight of composite sinks also means the sink is often not siliconed to the countertop — a faucet can be installed without fighting a bonded sink, but the sink may shift during the process. Placing a folded towel in the basin and resting the flashlight on it rather than the deck prevents scratches during the under-sink installation.
Water Pressure and Flow Rate Considerations
Kitchen faucets are regulated to a maximum flow rate of 2.2 gallons per minute (gpm) under federal WaterSense standards. Some high-efficiency faucets are rated at 1.5 or 1.8 gpm. Low flow rate can indicate either a water-efficient faucet design or a supply pressure problem that the faucet is not responsible for.
If a newly installed faucet has noticeably lower flow than expected, check supply pressure at the shutoff valve before adjusting or returning the faucet. Whole-house pressure below 40 psi will produce reduced flow at any faucet. Pressure between 40 and 80 psi is normal. Pressure above 80 psi is above the residential standard — a pressure-reducing valve (PRV) should be checked or installed at the main. Most quality faucets include a flow restrictor insert in the aerator. Removing this insert increases flow rate above the WaterSense rating but is not recommended for long-term use as it accelerates aerator clogging in hard water areas.
Post-Installation Leak Testing Protocol
A systematic leak test after faucet installation prevents water damage from slow drips that might not be noticed until cabinet damage occurs.
After reconnecting the supply lines and turning on the shutoff valves, perform the test in this sequence: First, open the cold-water handle only and let the system pressurize for 30 seconds. Inspect both supply connections — at the shutoff valve and at the faucet inlet — with a paper towel pressed firmly against each connection. A damp paper towel confirms a slow drip that would not be visible to the eye. Next, open the hot-water handle and repeat. Then check under the sink at the base of the drain — faucet installation sometimes disturbs the P-trap slip joints; press the paper towel around the P-trap connections as well.
If any connection leaks, shut off the supply at the valve and address: at a supply line compression fitting, add PTFE tape to the male threads and re-tighten; at a braided line with a rubber-washer fitting, tighten 1/8 turn more — do not overtighten. At the faucet base, check the mounting nut. At the P-trap, tighten the slip-joint nut hand-tight plus one quarter turn with channel-lock pliers. Re-test after each correction. Do not consider the installation complete until a full 60-minute pressurized test with no damp paper towel anywhere under the sink.
Aerator Maintenance After Installation
The aerator — the small screen assembly at the tip of the faucet spout — catches sediment and debris flushed from the supply pipes during and after installation. In the first 48 hours after installation, run the faucet briefly and then remove and rinse the aerator to clear any installation debris. Failure to do this is the most common cause of a new faucet appearing to have low flow — debris in the aerator screen restricts flow significantly. The aerator threads off counterclockwise (facing up into the spout) by hand or with a cloth-padded wrench. Rinse under running water and reinstall.
When to Call a Pro
Call a licensed plumber if: the shutoff valves under the sink are corroded shut or broken; the supply pipes are galvanized steel (not copper or PEX) and the connections cannot be made with standard compression fittings; or the drain needs to be modified to accommodate a new faucet with a built-in sprayer requiring a new hole. The faucet swap itself is a DIY task; corroded supply infrastructure is not.
This guide covers replacing a kitchen faucet — shutting off supply, removing the old faucet, installing the new faucet and deck plate, connecting braided stainless supply lines, and confirming a leak-free installation. The hardest part is working in a cramped under-sink space; the most common errors are under-tightening the mounting nut and reusing old supply lines.
Materials: new kitchen faucet, deck plate (if covering 3 holes with a single-hole model), new 16–20-inch braided stainless supply lines (3/8-inch compression × 1/2-inch IPS), PTFE plumber's tape, plumber's putty or silicone if faucet has no base gasket.
Step 01 — Shut Off the Water Supply
Turn both angle-stop shutoff valves fully clockwise under the sink. Open the faucet to bleed pressure. If the valves do not fully stop the flow, turn off the main house shutoff. Place the bucket under supply connections before disconnecting anything.
Step 02 — Remove the Old Faucet
Disconnect both supply lines from the faucet inlet shanks with the basin wrench. Remove the mounting nut(s). Lift the old faucet out from above. Clean the sink deck of mineral deposits, old putty, and silicone — a clean, dry deck ensures the new faucet's base seal works correctly.
Apply plumber's putty or silicone to the underside perimeter of the deck plate, set over the holes, and install mounting hardware from below. Wipe excess putty. Allow silicone to cure 30 minutes if used.
Step 04 — Feed Inlet Lines and Install Gasket or Putty
Insert the faucet through the deck hole from above. If the faucet includes a base gasket, no additional sealant is needed. If not, apply a 3/8-inch rope of plumber's putty around the underside of the faucet base before inserting.
Step 05 — Secure the Mounting Nut
From under the sink, tighten the mounting nut with the basin wrench until the faucet does not rotate when the handle is turned. This step is the most commonly skipped or undertightened — a loose faucet eventually breaks the supply connections below.
Step 06 — Connect New Supply Lines
Never reuse old supply lines — replace them. Apply 2 wraps of PTFE tape to all male threaded connections. Finger-tighten, then 1/4 to 1/2 turn further with pliers. Do not overtighten — the rubber washer inside the fitting provides the seal; overtightening distorts it. Confirm hot connects to the left (red) inlet, cold to the right (blue).
Step 07 — Turn Water On Slowly and Inspect
Open each shutoff valve 1/4 turn, wait 30 seconds. Check all four supply line connection points. Open the faucet and run for 60 seconds. Any threaded drip: add PTFE tape and re-tighten. Any base drip: re-tighten the mounting nut. A drip at the supply line fitting body: overtightened and cracked — replace that line.
Step 08 — Install Handle Hardware and Test
Install decorative trim and handle caps. Test hot and cold water separately. If supply lines chatter or vibrate, gently reposition them to relieve overly tight bends.
Always replace supply lines: Old rubber-core lines cost $10 to replace and thousands of dollars when they burst. New lines every faucet swap is standard practice.