How to Replace a Bathroom Faucet

Difficulty: Medium • Time: 90 min active, 120 min total • Estimated cost: $40-200 • Safety: DIY-friendly

Overview

Replacing a bathroom faucet is one of the most satisfying DIY plumbing upgrades — you're working in a confined space, but there's no soldering, no permits required, and the payoff is immediate. A new faucet can transform the look of an entire bathroom.

The most important thing before you start is buying the right faucet. You need to know your sink's hole configuration: single-hole (one faucet handle with integrated spout), centerset (two handles and spout as one unit, with holes 4 inches apart), or widespread (two separate handles and a spout, with holes 6-8 inches apart). Most bathroom sinks are centerset. Check under your sink and count the holes before buying.

Budget 90-120 minutes for a first-timer. The hardest part is usually working under the sink in an awkward position — a basin wrench makes this dramatically easier.

Tools Needed

Basin wrench (essential — makes under-sink work possible)
Adjustable wrench
Plumber's putty or silicone sealant
Bucket and towels
Flathead and Phillips screwdrivers
Flashlight or headlamp
Utility knife

Materials Needed

New bathroom faucet (centerset, single-hole, or widespread to match your sink) — $40-200
Basin wrench — $15-25
Flexible supply lines (10" or 12", if not included with faucet) — $8-15
Plumber's putty — $4-7
Teflon tape — $3-5

Step-by-Step Instructions

Shut off water and clear out under the sink: Turn both shut-off valves (hot and cold) under the sink clockwise until fully closed. Turn the faucet handles on to release pressure and drain the lines. Place a bucket under the supply line connections to catch residual water. Clear everything out from under the sink — you'll need room to work.
Disconnect the supply lines: Using an adjustable wrench, unscrew the supply line nuts from the shut-off valves (bottom connection) and from the faucet tailpieces (top connection). These are usually 3/8-inch compression fittings. Have your bucket ready — each line will drain a cup or two of water. If the lines are old and stiff, this is a good time to replace them with new braided stainless lines.
Disconnect the drain linkage: Most bathroom faucets include a pop-up drain stopper that's connected to the faucet via a thin rod and pivot mechanism. Under the sink, look for a horizontal pivot rod going into the drain pipe, held in by a clip. Pull the clip and pull out the pivot rod. The vertical lift rod passes through the faucet body — you'll pull this out when you remove the faucet. Some faucets have a separate drain assembly — just loosen the pivot rod connection.
Remove the old faucet: Under the sink, use the basin wrench to unscrew the mounting nuts holding the faucet to the sink deck — there's usually one or two nuts, one per tailpiece. Basin wrenches are specifically designed to reach up in tight spaces where your hands can't reach. Once the nuts are off, lift the faucet out from the top. Scrape away any old putty or sealant from the sink surface with a plastic scraper or utility knife.
Install the new faucet: Read the instructions included with your new faucet — brands vary. Most faucets have a deck plate or gasket that goes between the faucet body and the sink. If the faucet uses plumber's putty, roll a rope of putty and press it under the deck plate before setting it in place. If it uses a rubber gasket (more common now), just set it in place dry. Insert the faucet through the hole(s) from the top, thread the mounting hardware from below, and tighten the mounting nuts with the basin wrench until snug.
Connect the supply lines: Wrap the faucet tailpiece threads with 2-3 wraps of Teflon tape. Attach the new supply lines to the faucet tailpieces first (hand-tight plus a quarter turn with a wrench). Then connect the other ends to the shut-off valves. Don't overtighten — these are compression fittings and overtightening will damage them. Hand tight plus a quarter turn is usually sufficient.
Install the drain assembly: Your new faucet should include a new drain assembly. Apply plumber's putty around the underside of the drain flange, insert it through the drain hole from the top, and hand-tighten the drain nut from below. Insert the pivot rod through the horizontal opening in the drain pipe, hook it through the drain stopper loop, and secure the clip. Thread the lift rod down through the faucet body and clip it to the pivot rod connector bar. Test the stopper action before finishing.
Turn on water and check for leaks: Slowly open both shut-off valves. Turn on the faucet and let water run for 30 seconds. Shine a flashlight on every connection under the sink: supply line fittings at the valve and at the faucet, and the drain body connection. Any drip means a connection needs to be tightened slightly. A slow drip now will become a steady drip or leak within weeks — fix it before closing up.

When to Call a Professional

Call a plumber if the shut-off valves under the sink are frozen, corroded, or begin leaking when you try to close them (the valves need to be replaced before any faucet work can happen), if you discover corrosion or damage to the drain tailpiece or P-trap, or if you're replacing a faucet on an older home with galvanized or copper supply lines (connections to old pipe types require different fittings and more experience).