Overview

Replacing a faucet means removing an old, worn, or outdated kitchen or bathroom sink faucet and installing a new one in its place, reconnecting the water supply lines and drain-adjacent hardware as needed. It's a reasonable weekend project for a homeowner comfortable working in a cramped cabinet with hand tools, though tight spaces and corroded old fittings can make it more frustrating than it sounds.

Tools & materials

  • New faucet (matched to your sink's hole configuration and finish preference)
  • Basin wrench
  • Adjustable wrench or wrench set
  • Slip-joint pliers
  • Screwdriver
  • Bucket and old towels
  • Flashlight or headlamp
  • Plumber's tape (PTFE tape)
  • Plumber's putty or the gasket included with the faucet
  • Penetrating oil (for stubborn corroded nuts)
  • New flexible supply lines, if the old ones are worn or the wrong length

Steps

  1. Clear out the cabinet under the sink and lay down towels; keep a flashlight handy since the workspace is dark and cramped.
  2. Shut off the hot and cold shutoff valves under the sink, then open the faucet handles to release pressure and confirm the water is actually off.
  3. Place a bucket under the connections and disconnect the supply lines from the shutoff valves and from the faucet tailpieces, using an adjustable wrench or basin wrench as needed.
  4. Disconnect any sprayer hose, soap dispenser line, or garbage disposal connection that shares the same deck as the faucet.
  5. Use a basin wrench to reach up and loosen the mounting nuts holding the old faucet to the underside of the sink, then lift the old faucet out from above.
  6. Scrape off old putty or sealant residue from the sink deck and clean the surface so the new faucet will sit flush and seal properly.
  7. Assemble the new faucet per its instructions, apply plumber's putty or seat the included gasket, and insert it through the mounting holes from above.
  8. From below, thread on the mounting nuts or bracket by hand first to avoid cross-threading, then snug them with the basin wrench — tight enough to stop movement, not overtightened.
  9. Wrap the threads of the supply line connections with plumber's tape, then reconnect the new supply lines to both the shutoff valves and the faucet inlets.
  10. Reconnect any sprayer, soap dispenser, or disposal hose that was part of the original setup.
  11. Remove the faucet's aerator, then turn the shutoff valves back on slowly and run the water for a minute to flush out any debris before replacing the aerator.
  12. Check every connection for drips, run both hot and cold water, and test the sprayer or pull-down head if included.

Safety warnings

  • Always shut off the water supply at the valves under the sink (and confirm at the main shutoff if those valves are unreliable) before disconnecting any line.
  • Wear eye protection if using a hacksaw or reciprocating saw to cut through a stuck supply line or corroded nut.
  • Keep a bucket and towels in place — even a shut-off line can hold residual water that spills when disconnected.
  • Thread all nuts and fittings by hand before using a wrench to avoid cross-threading and stripping soft metal or plastic parts.
  • If a shutoff valve is seized or won't fully stop the flow, don't force it — use the home's main shutoff instead of working against running water.
  • Support your weight carefully when working on your back under the sink; clear away sharp tools before reaching underneath.

When to call a pro

  • The shutoff valves under the sink are corroded, frozen, or leak when turned, and won't isolate the water safely on their own.
  • You discover soft, water-damaged, or moldy cabinet flooring behind the sink, which points to a longer-standing leak needing more than a faucet swap.
  • The supply lines run back to old, hard-to-access shutoffs or galvanized pipe that needs cutting, soldering, or repiping.
  • You need to relocate the faucet holes or resize the sink deck cutout, which involves modifying the countertop or sink itself.
  • After installation you still find leaks at a joint you can't get to seal even after retightening and re-taping the connection.

Cost estimate

$100–$300 (faucet plus incidental parts; more for a premium faucet)

Sources