Caleb MorganBy Caleb Morgan

Updated November 2026

To repair a leaking faucet, you shut off the water supply, find out whether the leak comes from a worn washer, an O-ring, a cartridge or a valve seat, and replace that part. Most compression and cartridge faucets can be fixed in under an hour with basic hand tools. This guide walks through how to repair a leaking faucet from diagnosis to reassembly.

Identify Where the Leak Is Coming From

The location of the leak tells you which part has failed. A steady drip from the spout usually means the seal inside the faucet is worn. Water leaking from the base of the handle or around the body points to a failed O-ring or packing nut. Before you take anything apart, run the faucet and watch closely to see which of these you are dealing with.

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

How to Repair a Leaking Faucet, Step by Step

  1. Shut off the water at the under-sink supply valves. If they are stiff or do not close fully, shut off the main house valve.
  2. Open the faucet to drain remaining water and relieve pressure.
  3. Plug the sink drain so small parts cannot fall in.
  4. Remove the decorative cap and handle screw, then lift off the handle.
  5. Take out the packing nut or cartridge retaining clip, depending on your faucet type.
  6. Inspect the washer, O-ring, cartridge or valve seat for cracks, grit or flattening.
  7. Replace the worn part with an identical replacement. Bring the old part to the store to confirm the match.
  8. Apply a thin coat of plumber’s silicone grease to new O-rings and cartridge seals.
  9. Reassemble in reverse order, tighten snugly without overtightening, then turn the water back on slowly.

Compression Faucets vs. Cartridge Faucets

Compression faucets use a rubber washer that presses against a metal valve seat. When the washer wears, water seeps past it. You can often replace the washer and the seat with a seat wrench. Cartridge faucets use a single sealed unit. If the cartridge leaks, you usually replace the whole cartridge rather than individual seals. Manufacturers such as Delta and Moen sell model-specific cartridges, so note the brand and model number before ordering.

Tools and Supplies You Will Need

  • Adjustable wrench and basic screwdriver set
  • Replacement washer, O-ring or cartridge matched to your faucet
  • Plumber’s silicone grease
  • Old towel or rag to protect the finish
  • Phone camera to photograph the disassembly sequence
  • A cartridge puller helps you remove a stuck cartridge without scratching the faucet body. View on Amazon
  • A seat wrench fits the valve seat in many compression faucets and avoids rounding it off. View on Amazon
  • Plumber’s silicone grease keeps new O-rings sealing and turning smoothly. View on Amazon

Common Mistakes to Avoid

  • Skipping the water shutoff. Even a closed faucet can still have pressure in the lines.
  • Replacing parts without matching the brand and model, which often leads to a second leak.
  • Overtightening the packing nut or handle screw, which can crack plastic parts or strip threads.
  • Forgetting to plug the drain, so a tiny washer disappears down the pipe.
  • Ignoring a worn valve seat. If a new washer still drips, the seat is often the cause.

For a more detailed walkthrough of cartridge swaps, see Replace Kitchen Faucet Cartridge: Step-by-Step Repair Guide. If you are working on a Moen unit, Moen Kitchen Faucet Dripping: 6 Causes and How to Fix Each One covers the most common failure points. Owners of Delta faucets may also find Delta Faucet Repair Kits: How to Choose and Use the Right One useful when sourcing parts.

FAQ

Do I need to turn off the main water supply to fix a faucet?

Usually no. Most sinks have individual shutoff valves under the cabinet that isolate that faucet. If those valves are stuck or missing, shut off the main house valve instead.

How long does it take to repair a leaking faucet?

Many homeowners finish a washer or cartridge repair within about an hour, though first-time repairs often take longer. Plan extra time if corrosion makes parts hard to remove.

When should I call a plumber?

Call a licensed plumber if the valve body is cracked, the pipes leak behind the wall, or you cannot identify the faucet type. Consult a professional before doing any work involving gas or main water lines.

Conclusion

Learning how to repair a leaking faucet comes down to finding the source, shutting off the water, and replacing the worn washer, O-ring or cartridge. Matching the part to your faucet brand and model prevents most repeat leaks. With a few basic tools and patience, most drips can be stopped in a single afternoon.

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Caleb Morgan

About Caleb Morgan

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