How to Replace a Bathroom Sink Faucet: A Step-by-Step Guide for Homeowners

If you have been staring at a leaky, corroded, or just plain ugly bathroom faucet for years, you might think replacing it requires a call to a plumber and a hefty bill. The good news is that swapping out a bathroom sink faucet is one of the most straightforward DIY projects you can tackle, even if you have never held a wrench before. With a little patience and the right hardware, you can transform your bathroom in an afternoon.

Before you start, you will need to gather some basic tools and materials. A basin wrench is the unsung hero of faucet replacement, because it reaches those tight spaces behind the sink where a regular wrench simply cannot go. You will also need an adjustable wrench, a screwdriver set, plumber’s putty or silicone caulk, a bucket or towel to catch drips, and of course your new faucet. Make sure the new faucet is designed for the number of holes in your sink—most bathroom sinks have three holes, but some have one or four. If your sink has three holes and your new faucet only needs two, you can buy a deck plate to cover the unused hole. Also check the supply line connections; most modern faucets use flexible braided hoses that connect directly to shutoff valves, which is much simpler than dealing with old copper or plastic tubes.

Start by turning off the water supply. Under your sink you will see two shutoff valves, one for hot and one for cold. Turn them clockwise until they stop. Then open the faucet handle to relieve any pressure and drain the remaining water. Place a bucket or towel underneath the sink to catch any water that spills when you disconnect the supply lines. Using your adjustable wrench or a basin wrench, loosen the nuts that connect the supply lines to the tailpieces of the old faucet. Once those are loose, you can unscrew them by hand.

Now you need to remove the old faucet itself. Reach underneath the sink and find the large mounting nuts that hold the faucet in place. These are usually plastic or brass and can be stubborn if they have been there for years. Use your basin wrench to loosen them, turning counterclockwise. If they are stuck, a spray of penetrating oil can help. Once the nuts are off, lift the old faucet out from above. You may need to wiggle it a bit, especially if there is old putty or caulk sealing the base. Scrape away any remaining putty or gunk from the sink surface with a putty knife, and clean the area thoroughly with a mild cleaner.

Installing the new faucet starts with reading the manufacturer’s instructions, because every faucet is a little different. In general, you will slide the rubber gasket that comes with the faucet onto the underside of the faucet base. Then feed the supply lines and mounting studs through the holes in the sink. If your sink does not have a gasket, you can apply a thin bead of silicone caulk around the base to create a watertight seal. From underneath, slide the mounting bracket or washers onto the studs and tighten the mounting nuts with your basin wrench. Be careful not to overtighten, as that can crack the sink or strip the threads.

Next, connect the supply lines. Attach the braided hoses from the faucet to the shutoff valves. Usually, these are hand-tightened, then given a quarter turn with a wrench to ensure they are snug. Do not overtighten them either, or you risk crushing the rubber o-ring inside the nut. Once both lines are connected, turn the shutoff valves back on slowly. Check for leaks at every connection point—where the hoses meet the valves, and where the hoses attach to the faucet. If you see a drip, tighten the nut just a little more.

Finally, install the faucet handle and the trim pieces. Many faucets come with a single lever that simply snaps on or is secured with a set screw. For two-handle faucets, you will attach each handle to the valve stem and secure it with a screw. Pop the decorative caps on if there are any. Turn on the water and test both hot and cold. Let the water run for a minute to flush out any debris that might have gotten into the lines during installation. Look under the sink one more time to confirm there are no slow drips.

If you notice a leak at the base of the faucet where it meets the sink, you may need to apply a little more silicone caulk around the edge and smooth it out with your finger. Wipe away any excess with a damp cloth. That is it—you are done. Your new faucet should work perfectly for years, and you saved yourself the cost of a plumber. Plus, you now have the confidence to tackle other bathroom hardware projects, like changing a showerhead or fixing a toilet flapper. Remember, the most important tool you have is the willingness to try. With a little effort and the right hardware, your bathroom can look and function like new.