Leaky Laundry Faucet: Causes, Fixes, and When to Call a Plumber

Why Your Laundry Faucet Leaks and How to Stop It

A leaky laundry faucet is one of the most common household plumbing issues, yet it is often ignored until the drip becomes a steady stream or the handle starts to feel spongy. Whether the leak comes from the spout, the base, or the packing nut, the root cause is usually wear on a washer, O-ring, or cartridge inside the valve. In some homes, hard water accelerates the decay of rubber parts, and in older buildings, corroded valve seats make even a new washer fail within months. Understanding what sits behind the handle helps you choose the right repair and avoid calling a plumber for a job you can manage with basic tools.

Common Causes of a Leaky Laundry Faucet

• Worn rubber washers: The oldest cause. The washer compresses against the valve seat each time you turn the faucet off; over time it hardens, cracks, or flattens and loses its seal, letting water seep past the stem.
• Damaged O-rings: Located around the handle or cartridge, these keep water from leaking at the spindle. When they dry out or split, you get a drip even with the handle closed.
• Corroded valve seat: Mineral deposits from hard water erode the metal surface the washer presses against, so a new seal fails quickly.
• Loose packing nut: The nut that holds the stem in place can work itself free over time, letting water seep around the handle. Sometimes it just needs a gentle tightening; other times the threads are stripped and require replacement.
• Cartridge wear: In modern single-handle faucets, the cartridge itself can crack or wear out, causing water to leak from the spout or the base.

Parts You Will Need

• Replacement washers (often rubber, sometimes silicone or ceramic)
• O-ring kit sized to your faucet model
• Valve seat repair kit or a new cartridge
• Packing washer or new packing nut
• Plumber's tape (Teflon tape)
• Adjustable wrench, screwdrivers, and a basin wrench

Step-by-Step Repair Guide

Turn off the water supply. Locate the shutoff valves under the sink and close them. Run the faucet to release pressure and confirm the water is off before you work.

Remove the handle. Pry off the decorative cap, unscrew the handle screw, and pull the handle straight off. If it is stuck, use a handle puller or wrap a cloth around it and gently tap with a wrench.

Inspect and replace the washer or O-ring. Pull out the stem assembly and look for the worn part. Take it to a hardware store to match the size exactly, or remove it and bring the whole assembly with you. Replace rubber washers with new ones of the same thickness. For O-rings, lubricate with plumber's grease before reinstalling.

Tighten or replace the packing nut. If the nut is merely loose, tighten it with a wrench. If the threads are damaged, replace the entire packing nut or the stem assembly.

Reassemble and test. Put the handle back on, turn the supply back on, and check for leaks. Run the water for a full minute. If drips continue, turn it off and confirm the washer is properly seated. A slight misalignment is enough to cause a persistent leak.

When to Call a Plumber

Call a professional if the valve seat is badly corroded, the threads inside the body are stripped, or the leak persists after replacing the washer and O-ring. Also call a plumber if you notice water pooling around the base when the faucet is off, which can signal a cracked body or a failed cartridge requiring specialized parts. Frequent repairs on an old faucet may be less cost-effective than replacing the entire unit, and a plumber can advise on modern, water-efficient models.

Prevention Tips

Replace washers every few years before they fail. Install a water softener if your home has hard water to reduce mineral damage. Avoid over-tightening handles, which accelerates wear on rubber seals. Choose quality faucets with metal valve seats for longer life and fewer repairs.