How to Replace a Bathroom Faucet

Replacing a worn, leaking, or outdated bathroom faucet is a highly rewarding project that saves $150–$300 in plumber labor. Modern faucets with integrated supply lines and drop-in connections make the job manageable for most homeowners.

This guide is based on manufacturer installation instructions and standard plumbing codes. We have not performed hands-on testing. Shut off the water supply and have towels and a bucket ready.

---

Project Specifications

• Difficulty: Medium (working in tight spaces)
• Working Time: 1–2 hours
• Total Time: 2 hours
• Cost: $50–$150 (faucet + supplies)

---

Tools & Materials

• Tools: Adjustable wrench (8-inch or 10-inch), channel lock pliers, basin wrench (essential for reaching tight mounting nuts behind the sink), bucket and rags, flashlight or headlamp.
• Materials: New centerset or widespread faucet, braided stainless steel supply lines (typically 3/8-inch compression to 1/2-inch FIP), plumber’s putty or silicone (if required by manufacturer), and Teflon thread tape.

If you’re still building out your basic tool collection, our essential homeowner tools guide covers the hand tools worth keeping on hand.

---

Step-by-Step Instructions

Step 1: Shut Off Water

Locate the hot and cold water shut-off valves beneath the sink. Close both valves by turning them clockwise. Open the faucet handles above the sink to relieve pressure and drain any remaining water.

Step 2: Disconnect Supply Lines

Place a bucket under the shut-off valves. Using an adjustable wrench, loosen and remove the flexible supply lines from both the valves and the faucet shanks. Drain the excess water into the bucket.

Step 3: Remove Old Faucet & Clean Sink Deck

Under the sink, remove the mounting nuts securing the faucet using a basin wrench. Lift the old faucet out from the top of the vanity.

• Disconnect the pop-up drain linkage rod and loosen the large locknut securing the old drain flange.
• Scrape away old dried putty or mineral buildup from the sink deck using a plastic putty knife to avoid scratching the porcelain or stone.

Step 4: Install New Faucet

Many modern faucets include a rubber sealing gasket on the bottom. If yours does not, apply a 1/4-inch bead of plumber’s putty along the underside perimeter.

• Lower the faucet shanks through the mounting holes in the sink deck.
• Slide the washers over the shanks from below and tighten the mounting nuts by hand. Snug them with a basin wrench — do not overtighten on porcelain. Wipe away any putty squeeze-out from the top.

Step 5: Install Drain & Connect Lines

Apply a ring of plumber’s putty around the underside of the new drain flange and press it down into the sink drain hole.

• From underneath, slide the rubber gasket, washer, and locknut over the drain body and tighten. Reconnect the slip-joints to the P-trap and hook up the pop-up linkage.
• Apply Teflon tape (3-4 wraps clockwise) to the threads of the faucet shanks and shut-off valves. Thread the new supply lines on, hand-tighten, and then add another quarter-turn with a wrench.

Step 6: Flush & Test

Unscrew the aerator nozzle from the spout. Turn the water valves on slowly and open both hot and cold faucet handles for 1 minute to flush out any debris or air pockets. Reinstall the aerator and check all joints for leaks.

---

Common Mistakes & Troubleshooting

• Overtightening Plastic Nuts: Hand-tighten plastic nuts under the vanity. Metal tools can easily strip plastic threads, causing slow leaks.
• Cross-Threading: If a nut does not turn smoothly, back it off and realign. Cross-threaded lines will leak under pressure.
• Micro-Drips: If leaks persist after tightening, turn off the water, check that the rubber washers are seated flat inside the fittings, apply Teflon tape, and retighten.

---

Safety & When to Call a Pro

• Seized Valves: If the shut-off valves under the sink are frozen, corroded, or leak when turned, shut off the main water valve to the house and call a plumber.
• Damaged Pipes: Stop if you encounter damaged copper lines, galvanized iron pipes, or rot in the vanity floorboards.
• Lead Precautions: Homes built before 1978 may have lead solder in copper joints — use proper precautions.

---

Cleanup

1. Dry all pipes and structural wood flooring inside the vanity cabinet.
2. Leave the empty bucket under the drain lines for 24 hours. Check it occasionally to verify no slow leaks occur during use.
3. Dispose of old faucets and piping according to local recycling regulations.

---

Authoritative Sources & Citations

1. International Code Council: 2021 International Plumbing Code Section 607 (Accessed July 2026) — Material standards and pressure limits for residential water systems.
2. Moen Incorporated: Moen Faucet Installation Help Guide (Accessed July 2026) — Torque limits, alignment parameters, and tool recommendations.

---

Related DwellNinja Guides

• Best Basic Tool Kits for New Homeowners
• Essential Tools Every Homeowner Should Own