Miles SinclairBy Miles Sinclair

Updated November 2026

A kitchen faucet is leaking for one of a few predictable reasons: a worn cartridge, a failed O-ring or washer, a loose connection, or a damaged spout seal. This guide shows you how to locate the leak, shut off the water safely, and make the most common repairs yourself. Most drips can be fixed in under an hour with basic hand tools.

Find Where the Water Is Coming From

Before you take anything apart, figure out exactly where the water is escaping. The location tells you which part has failed.

Shopping for one? See our guide: 6 Best Moen Leaking Kitchen Faucet Repair Parts (2026).

  • Dripping from the spout tip: Usually a worn cartridge or valve seat inside the faucet body.
  • Leaking around the handle: Typically a worn O-ring, packing nut or cartridge seal.
  • Water pooling at the base or under the sink: Often a loose mounting nut, a cracked supply line, or a faulty connection under the sink.
  • Leaking from the spray hose or sprayer head: Commonly a damaged hose, a worn diverter valve or a loose hose connection.

Dry the faucet with a towel, then run the water for a few seconds and watch closely. If water appears only when the handle is on, the problem is inside the faucet body rather than in the supply lines.

Shut Off the Water and Prepare

Turn off the water supply under the sink before you remove any parts. If the shutoff valves are stiff or do not close fully, shut off the main house valve instead. Open the faucet to drain any remaining water from the lines.

Gather these tools and supplies:

  1. Adjustable wrench and basin wrench
  2. Plumber’s grease and replacement O-rings or cartridge
  3. Flathead screwdriver and Allen wrenches (often included with the faucet)
  4. Soft cloth or towel to protect the finish
  5. Small bowl or tray for holding screws and small parts

Repair the Most Common Leak Sources

Replace a Worn Cartridge or Valve

If water drips from the spout even when the handle is fully closed, the cartridge is the likely culprit. Remove the handle, unscrew the retaining nut or clip, and pull out the cartridge. Note how it is oriented, then install the matching replacement with the same alignment. Our guide on Replacing Kitchen Faucet Cartridge: A Step-by-Step Guide for Beginners walks through this process in detail.

Replace O-Rings and Seals

Leaks around the base of the handle usually come from worn O-rings. Remove the handle and any cap, take out the old O-ring, and clean the groove. Coat the new O-ring with plumber’s grease so it seats smoothly and resists wear. Do not use petroleum jelly, which can degrade rubber over time.

Tighten Loose Connections

If the leak appears at the base or under the sink, check the mounting nuts and supply line connections. Tighten them firmly with a wrench, but do not overtighten, since that can crack plastic nuts or deform gaskets. Replace any supply line that shows cracks, bulges or corrosion.

Test the Repair and Check for Problems

Turn the water supply back on slowly. Open the faucet, then close it, and check every joint and connection for moisture. Wait at least 15 minutes before deciding the repair has worked, since slow leaks can take time to show up. If the drip continues, double-check that the cartridge or O-ring is seated correctly and that no debris is trapped in the valve.

Common Mistakes

  • Forgetting to shut off the water supply before disassembly.
  • Installing a cartridge backward or out of alignment.
  • Using too much force on plastic nuts, which can crack them.
  • Skipping plumber’s grease, which shortens O-ring life.
  • Buying a replacement part without confirming the faucet brand and model.

A basin wrench reaches the mounting nuts behind the sink where a standard wrench cannot. Plumber’s grease keeps O-rings flexible and helps them seal properly. Keep a labeled bag for small screws and parts so nothing gets lost during reassembly.

FAQ

Why does my kitchen faucet keep dripping after I close the handle?

A worn cartridge or valve seat is the most common cause. Replacing the cartridge usually stops the drip, provided the replacement matches your faucet brand and model.

Can I fix a leaking faucet without shutting off the water?

No. Always shut off the supply valves under the sink first, or the main house valve if the local valves fail. Working on a pressurized line can spray water and damage the area.

When should I call a plumber about a leaking faucet?

If you find corroded supply lines, cracked fittings, or water damage to the cabinet floor, a licensed plumber should inspect the work. Consult a professional whenever the repair involves gas lines, electrical components or structural damage.

Conclusion

A leaking kitchen faucet is usually traceable to a worn cartridge, O-ring or loose connection. Identify where the water escapes, shut off the supply, and replace the failed part with a matching component. Careful work and the right tools will stop most drips for good.

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Miles Sinclair

About Miles Sinclair

Miles Sinclair is part of our editorial team and reviews and edits our kitchen faucets & sinks guides, checking product details against manufacturer specifications and owner feedback.