A dripping, corroded, or outdated faucet drags down the entire look of your bathroom vanity. Learning how to replace a bathroom faucet saves you the $150 to $300 a plumber charges for a straightforward swap. The job takes 30 to 60 minutes with basic tools, no soldering, and no special skills. As long as you can turn a wrench and crawl under a sink, you can handle this project on a Saturday morning and enjoy the upgrade by lunch.
Part of our Bathroom Remodeling & Flooring guide — explore the full guide →
Choosing the Right Replacement Faucet
Before shopping, identify your sink’s hole configuration. Look under the vanity or measure the holes on top. Bathroom sinks come in three common setups:
- Single-hole: One center hole, typically 1.375 inches in diameter. Accepts single-handle faucets or single-hole two-handle models with a deck plate.
- Centerset (4-inch): Three holes spaced 4 inches center-to-center. The most common configuration in standard bathrooms. Centerset faucets come as one unit with handles and spout on a single base plate.
- Widespread (8-inch): Three holes spaced 8 inches or more center-to-center. Each handle and the spout mount separately, connected by flexible hoses underneath.
Match your new faucet to the existing hole count and spacing. Changing configurations requires drilling new holes in the sink or countertop, which is a separate and more involved project. Stick with the same type for a simple swap.
Tools and Materials
Most faucet replacements require only a few basic tools. Gather these before you start:
- Basin wrench — essential for reaching mounting nuts in tight spaces behind the sink basin. About $15 at any hardware store.
- Adjustable wrench or channel-lock pliers
- Bucket and towels for residual water
- Plumber’s putty or silicone caulk (check your faucet’s instructions for which is recommended)
- Flashlight or headlamp — the underside of a vanity is dark
- Penetrating oil (WD-40 or PB Blaster) for corroded nuts
Your new faucet kit should include supply line connectors, a gasket or deck plate, and mounting hardware. Inspect the package before starting to confirm all parts are present.
Removing the Old Faucet
Turn off both hot and cold shut-off valves under the sink. Turn the faucet on to release remaining water pressure, then place a bucket underneath the supply line connections. Disconnect the supply lines from the shut-off valves using an adjustable wrench. Some water will drain out, so keep your towels ready.
Reach behind the sink basin with a basin wrench and loosen the mounting nuts that hold the faucet to the sink. These nuts are often corroded after years of humidity exposure. Spray penetrating oil on them and wait 10 minutes if they resist turning. Once the mounting nuts are off, lift the old faucet straight up and off the sink. Clean the sink surface around the mounting holes with a plastic scraper and rubbing alcohol to remove old putty, caulk, and mineral deposits.
Installing the New Faucet
Read the manufacturer’s instructions for your specific model. While the general process is similar across brands, gasket placement and mounting hardware vary. If your faucet includes a rubber or foam gasket, place it over the mounting holes before setting the faucet. If no gasket is included, apply a thin rope of plumber’s putty around the base plate.
Feed the supply lines and mounting hardware down through the sink holes from above. Position the faucet so the spout is centered over the drain. Underneath, hand-thread the mounting nuts onto the faucet shanks, then tighten with a basin wrench. Snug is sufficient. Over-tightening can crack porcelain sinks or strip the threads.
Connect the hot and cold supply lines to the corresponding shut-off valves. Hot is on the left, cold on the right when facing the sink. Hand-tighten the coupling nuts, then give them a quarter turn with a wrench. Do not use thread tape on compression fittings, as they seal with the compression ring.
Testing for Leaks
Before closing up, remove the faucet aerator to flush debris from the new lines. Turn on the shut-off valves slowly, one at a time. Let water run for 30 seconds to clear any particles from the supply lines and faucet body. Check every connection point underneath for drips: both supply line connections at the valves, both connections at the faucet, and the mounting nut seals.
Dry each connection with a paper towel and check again after five minutes. Slow leaks sometimes take a minute or two to appear. If you find a drip, tighten the affected connection an eighth turn at a time until it stops. Reinstall the aerator once the water runs clear. Run both hot and cold to confirm proper operation and check the drain stopper linkage if your new faucet includes a pop-up drain assembly.
Installing a Pop-Up Drain Assembly
Many faucet kits include a new pop-up drain stopper and lift rod. If yours does, remove the old drain assembly by unscrewing the drain flange from above while holding the drain body below with pliers. Clean the drain opening in the sink.
Apply plumber’s putty under the new drain flange and press it into the sink opening from above. Thread the drain body onto the flange from below and tighten until the putty squeezes out slightly. Connect the horizontal pivot rod to the clevis strap attached to the lift rod. Adjust the pivot rod length so the stopper opens and closes fully when you push the lift rod behind the faucet. Trim excess putty from around the drain flange with a plastic putty knife.
Troubleshooting Common Issues
Low water pressure after installation usually means a clogged aerator. Remove it and clean the screen. If pressure is still low, check that both shut-off valves are fully open and that the supply lines are not kinked under the sink.
A faucet that wobbles on the sink means the mounting nuts are not tight enough or the rubber gasket is misaligned. Tighten from below and check that the gasket sits flat against the sink surface. Persistent dripping from the spout after installation indicates a defective cartridge, which is covered under the manufacturer’s warranty on new faucets. Contact the manufacturer for a replacement cartridge rather than attempting to repair a brand-new unit.
Before Changing Out a Faucet: Water Shutoff, Pressure, and Supply Line Checks
Most frustrating faucet swaps go wrong before the old fixture ever comes off. A five-minute inspection under the sink tells you whether the job will be a quick swap or whether you need extra parts, and it keeps a small project from turning into a flooded vanity cabinet.
Confirm the Water Really Shuts Off
Turn each shutoff valve clockwise until it stops, then open the faucet handles fully. If water keeps trickling after a minute, the valve is not sealing. Older multi-turn valves often seize or weep once they are finally moved after years of sitting open. In that case, close the main water valve for the house instead, and plan to replace the worn stops while the water is already off. Working against a leaking shutoff means every connection you loosen will keep dripping.
Relieve Pressure and Drain the Lines
With the valves closed, leave the faucet open in both the hot and cold positions until nothing more comes out. If you shut off the main, also open a lower faucet in the house, such as a basement or first-floor tap, so the lines drain toward it rather than into your lap when you loosen a nut. Keep a shallow container and a towel directly under each connection.
Check What Your Supply Lines Need
- Connection sizes: Note the outlet size on each shutoff valve and the inlet type on the new faucet. Many faucets come with lines already attached; others need separate lines, so read the box before you leave the store.
- Length: Measure from valve outlet to faucet inlet and add a few inches so the line can curve gently without kinking.
- Condition: Replace old solid chrome tubes or aging plastic lines rather than reusing them. New braided lines are inexpensive compared with the damage from a failed connection.
Handle the Drain Safely
If anyone has recently poured a chemical drain opener into the sink, do not open the trap or pop-up drain until the product has been fully flushed with plenty of running water, and wear gloves and eye protection when you do. Never mix drain cleaners or follow one product with another, since some combinations react and release harmful fumes. A plastic drain snake or removing and cleaning the trap is the safer way to clear a slow bathroom sink before installing the new fixture.
Once the water is off, the lines are drained, and you have the right supply connections on hand, changing out a faucet becomes the straightforward job it should be.
