Install a New Bathroom Faucet

Replacing a bathroom faucet ranks among the most achievable plumbing upgrades you can do yourself. Whether you're swapping out a corroded chrome fixture or installing something with better water pressure and cleaner lines, the job involves straightforward disconnections and reconnections. The actual difficulty lies in one place: the tight space under the sink, where you'll be working in cramped quarters with your head tilted back. Getting comfortable with that constraint before you start makes the whole project move faster. A new faucet transforms how a bathroom feels every single day—it's one of those improvements you'll notice on day one and be glad about for years.

1. Kill the Water Supply First. Locate the shutoff valves under the sink—there are usually two, one for hot and one for cold. Turn both valves clockwise until they stop. If the valves are missing or stuck, shut off the main water supply to the house. Open the faucet to release any pressure in the lines and confirm the water is off.
2. Free Both Supply Lines. Place a bucket under the connections. Use an adjustable wrench to hold the fitting on the faucet body while you turn the nut counterclockwise with another wrench. Work slowly—old fittings can bind. Once both hot and cold lines are loose, unscrew them by hand and let any remaining water drain into the bucket.
3. Disconnect the Drain Rod. If your new faucet comes with a different drain setup or if the pop-up rod is integrated into the old faucet body, disconnect the drain. Use a wrench to loosen the connection under the drain. Most bathroom faucets have a pivot rod that controls the pop-up—pull it free and set it aside.
4. Unbolt the Old Fixture. From underneath, you'll find mounting nuts or bolts holding the faucet body to the sink. Use a basin wrench (a specialty wrench designed for tight spaces) or a regular wrench to turn these counterclockwise. Some faucets have plastic clips instead of bolts—pry these up and back. Once all fasteners are loose, push up on the faucet from below and it will lift free from above.
5. Scrape and Clean the Deck. With the old faucet out, you'll see caulk, mineral deposits, and years of buildup around the mounting holes. Scrape this away with a putty knife or old credit card. Wipe the area clean with a damp cloth. If you're installing a new faucet with a different hole count or spread, fill old holes with sink caulk and let it dry before moving forward.
6. Build the Base Unit. Lay out all the new faucet parts on a clean surface. Most faucets come with a rubber gasket, a mounting plate, and mounting bolts. Thread the gasket and mounting hardware onto the faucet body according to the manual. Hand-tighten everything at this stage—you'll adjust it once it's seated in the sink.
7. Seat the New Faucet. From above, lower the assembled faucet into the mounting holes. The spout and handles should sit centered and level. Slide the mounting plate under the sink deck. From below, hand-thread the mounting bolts or clips and tighten them evenly—go a quarter turn on one side, then the opposite side, to keep the faucet level. Tighten until the faucet is snug but not overtightened.
8. Attach Both Supply Lines. Take the hot supply line (marked if you did so earlier) and thread it onto the hot water fitting of the new faucet. Use two wrenches—one to hold the fitting body, one to turn the nut—and tighten until snug. Repeat for the cold line. Don't crank hard; hand-tight plus a quarter turn with a wrench is correct.
9. Restore Drain Function. If you removed the drain, reconnect it now. Hand-thread the connection, then tighten with a wrench. Thread the pop-up rod back through the horizontal pivot arm under the faucet body. Adjust it so that pushing down on the pop-up knob closes the drain fully and pulling it up opens the drain. The rod should slide smoothly without binding.
10. Check Everything for Leaks. Turn the shutoff valves back on, starting with the hot water. Open the faucet and let water run for 30 seconds to clear air from the lines. Check for leaks at every connection—supply lines, drain connection, and around the base of the faucet. Flush the system by turning the water on and off a few times to dislodge any debris.
11. Fine-Tune Flow and Temp. Most new faucets come from the factory with a limiter that reduces maximum flow. If the water pressure feels weak, check the manual for where to remove this limiter—it's usually a small cartridge or clip inside the spout or handles. Some faucets also have a mix adjustment screw that balances hot and cold—refer to the manual if the temperature swings too much.
12. Seal the Base Perimeter. Once you've confirmed no leaks, run a bead of silicone caulk around the perimeter where the faucet body meets the sink deck. Use a caulk gun and smooth the line with a wet finger. Let it cure for 24 hours before using the faucet. This seal prevents water from seeping under the deck and rotting the vanity.