What you need before you start

Replacing a faucet is a job most people can do in an afternoon with basic tools and no plumbing experience. You will need an adjustable wrench, a basin wrench (a specialized tool that costs $10 to $20 and makes the job much faster), a screwdriver, and a bucket or towel to catch water. Before you buy a new faucet, measure the distance between the holes on your sink — most are 4 inches or 8 inches center-to-center — and check whether your sink has one hole, two holes, or three holes. Take a photo of your current setup and bring it to the hardware store, or order online only after confirming the hole count and spacing.

Turn off the water supply under the sink. Look for two shut-off valves (one for hot, one for cold) and turn both clockwise until they stop. If you cannot find them or they do not work, turn off the main water supply to your house. Open the faucet to release any remaining pressure in the lines.

Key Takeaways

  • Measure the distance between sink holes and count how many holes your sink has before buying a replacement faucet, because faucets are not interchangeable.
  • Turn off the water supply under the sink before you disconnect anything, and open the faucet to release pressure.
  • A basin wrench ($10 to $20) makes removing the old faucet much faster than using an adjustable wrench alone.
  • Most new faucets come with supply lines and mounting hardware included, so you do not need to buy those separately.
  • The entire job usually takes one to three hours, and leaks at the base are the most common mistake — tighten the mounting nuts firmly but do not overtighten.

Removing the old faucet

Disconnect the supply lines by turning the nuts at the base of the faucet counterclockwise with an adjustable wrench. Have a bucket or towel ready — there will be water in the lines. If the nuts are stuck, spray them with penetrating oil and wait 15 minutes before trying again.

Locate the mounting nuts underneath the sink. These hold the faucet to the sink from below. Use a basin wrench to loosen them — it has a long shaft and a pivoting head that lets you reach into tight spaces. If you do not have a basin wrench, an adjustable wrench works but requires more maneuvering. Turn the nuts counterclockwise until they are loose enough to remove by hand. Lift the old faucet straight up and out of the sink. Clean away any old caulk or debris from the sink holes with a plastic scraper.

Installing the new faucet

Most new faucets come with a rubber gasket or mounting plate that sits on top of the sink. Insert the faucet tailpieces (the threaded rods that hang down) through the sink holes. From underneath, hand-tighten the mounting nuts onto the tailpieces, then use a basin wrench or adjustable wrench to tighten them firmly. Do not overtighten — you want them snug enough that the faucet does not move, but overtightening can crack the sink or strip the threads.

Connect the supply lines to the faucet inlets. Most new faucets come with flexible supply lines already attached; if yours did not, buy braided stainless steel lines rated for your water pressure (usually 80 PSI or higher). Hand-tighten the nuts first, then use an adjustable wrench to tighten them one more quarter-turn. Do not use excessive force — these connections leak more often from overtightening than from undertightening.

Testing for leaks

Turn the water supply back on slowly. Open the faucet and let water run for 30 seconds to flush out any debris from the lines. Check underneath the sink for drips at the supply line connections and at the base of the faucet where it meets the sink. If you see drips at the supply connections, turn off the water, tighten the nut one quarter-turn more, and test again.

If water is leaking from the base of the faucet where it sits on the sink, the mounting nuts may not be tight enough, or the gasket may not be seated properly. Turn off the water, remove the faucet, check that the gasket is clean and in the right position, and reinstall it. Leaks at the base are usually solved by tightening the mounting nuts more firmly. If the faucet still leaks after that, the gasket may be defective — contact the manufacturer or return the faucet.

Finishing touches

Once the faucet is installed and not leaking, caulk around the base where the faucet meets the sink. Use 100% silicone caulk, not acrylic, because it resists water better and lasts longer. explore a thin bead around the perimeter, smooth it with a wet finger, and let it cure for 24 hours before using the sink heavily.

If your new faucet has a sprayer or side spray, connect it to the outlet on the faucet body using the supply line provided. Test the sprayer before you finish. Some faucets have a diverter valve that switches water between the main spout and the sprayer — make sure both work and that water does not leak from the spout when the sprayer is in use.

Common mistakes and how to avoid them

The most frequent problem is a leak at the base of the faucet, which usually means the mounting nuts are not tight enough or the gasket is not seated properly. Tighten the nuts firmly but stop before you feel strong resistance — you are looking for snug, not maximum force. The second most common issue is leaking supply line connections, which happens when people overtighten the nuts. Hand-tighten first, then add only a quarter-turn with a wrench.

Another mistake is buying the wrong faucet for your sink. A single-hole faucet will not fit a two-hole sink without an adapter, and an 8-inch spread faucet will not work on a 4-inch sink. Measure twice and confirm the hole count before you purchase. If you order online and the faucet arrives, test-fit it before you remove the old one — if it does not match your sink, you can return it without having to reinstall your old faucet in a hurry.

When to call a plumber

If the shut-off valves under your sink do not work and you cannot turn off the main water supply, stop and call a plumber. Attempting to replace a faucet without being able to shut off the water will result in flooding. If you remove the old faucet and discover that the sink holes are cracked, stripped, or in the wrong positions, a plumber may need to repair or replace the sink itself.

If you have finished the installation and the faucet leaks from the base even after tightening the mounting nuts and reseating the gasket, the faucet may be defective. Contact the manufacturer first — many will replace a defective unit. If the manufacturer will not help, a plumber can diagnose whether the problem is the faucet or the sink, and recommend the next step.

Frequently Asked Questions

Do I need a basin wrench?

A basin wrench makes the job much faster and easier, especially in tight spaces under the sink. You can do the job with just an adjustable wrench, but you will spend more time contorting your arms and may scratch the sink. For $10 to $20, a basin wrench is worth buying if you plan to do this job yourself.

What if my faucet has a pop-up drain?

The pop-up drain is usually connected to the faucet body by a rod underneath the sink. Before you remove the faucet, disconnect this rod by unscrewing the nut that holds it to the faucet. When you install the new faucet, reconnect the rod the same way. If the new faucet does not have a pop-up drain connection, you will need to install a separate pop-up drain assembly in the sink hole.

Can I reuse the old supply lines?

Old supply lines can crack or develop weak spots over time. If they are more than 10 years old or show any visible damage, replace them. New braided stainless steel lines cost $5 to $15 per pair and are worth the investment — a burst supply line can cause significant water damage.

How tight should the mounting nuts be?

Tighten the mounting nuts until the faucet does not move when you push on it, then stop. You should feel moderate resistance, not extreme force. Overtightening can crack the sink or strip the threads on the tailpieces, making the problem worse than if you had left them slightly loose.

What if water is still leaking after I tighten everything?

Check the supply line connections first — turn off the water and tighten the nuts one quarter-turn more. If that does not work, turn off the water, remove the faucet, and inspect the gasket for damage or debris. Clean the gasket and the sink surface, reinstall the faucet, and test again. If leaking continues, the faucet may be defective and should be returned.