Why Is My Kitchen Sink Leaking? Common Causes and Fixes

A kitchen sink leaking isn’t just a nuisance—it can turn into a serious problem if left unchecked. Water damage can ruin cabinets, warp flooring, and even lead to mold growth. Many people don’t realize how fast a small drip can escalate into an expensive repair. That’s why it’s important to know the most common causes of sink leaks and the simple steps you can take to protect your home.

At Fisher & Son’s Plumbing, we’ve fixed hundreds of leaky sinks, and we know what to look for. Below, we’ll break down the usual suspects behind kitchen sink leaks, the signs to watch for, and how to fix them before they cause bigger problems.

Common Reasons for a Kitchen Sink Leaking

When you spot water under the sink, your first thought is usually: “Where’s that coming from?” The tricky part is that water can travel along pipes or drip from more than one source. Here are the main culprits:

1. Loose or Worn-Out Sink Drain

One of the most common issues is a sink drain leak. The drain assembly connects the sink bowl to the plumbing system. Over time, the putty or gasket around the drain can break down. When that happens, water slips through every time you run the tap.

• If the leak happens only when water is draining, the drain fitting is likely the problem.
• Replacing the drain seal or reapplying plumber’s putty often solves this issue.

2. Pipe Under Sink Leaking

Another big culprit is a pipe under the sink leaking. The P-trap and other drain pipes can loosen or crack over time. This is especially common in older homes or in places where pipes have been bumped during storage.

• A cracked pipe needs replacement, plain and simple.
• If the connections are just loose, tightening them with a wrench may stop the leak.

3. Leaky Faucet

Sometimes the problem isn’t under the sink at all. A worn-out faucet cartridge, O-ring, or washer can send water dripping down into the cabinet below.

• If water drips from the handle or around the base of the faucet, that’s usually a faucet issue.
• Replacing small internal parts often fixes the problem without needing a full faucet replacement.

4. Faulty Water Supply Lines

The supply lines that connect the faucet to your home’s water source can fail over time. A pinhole leak or a loose fitting can cause water to spray or drip below the sink.

• Braided steel hoses last longer than plastic ones and are less likely to burst.
• Always replace supply lines if they’re more than a few years old or show any sign of wear.

5. Damaged Seal Around the Sink

If water pools on your countertop, it can seep through the caulk or seal where the sink meets the counter.

• Over time, caulk dries out and cracks.
• Resealing the edges of the sink with waterproof silicone usually solves this issue.

Explore our plumbing services to find reliable solutions for leaks, clogs, repairs, and new installations, all handled by our experienced team.

How to Fix Kitchen Sink Leak Problems at Home

While some leaks need a plumber’s touch, a few can be handled with simple tools. Here’s what can help:

1. Tighten Loose Connections

Sometimes, the fix is as easy as tightening the slip nuts on your P-trap or drainpipe. Use channel-lock pliers or a wrench to snug them up. Don’t overtighten, or you risk cracking the fitting.

2. Replace Old Washers or Gaskets

For faucet or drain leaks, swap out worn washers and gaskets. These small parts are inexpensive but make a big difference.

3. Reapply Plumber’s Putty or Caulk‍

If the leak is around the sink drain or counter seal, clean out the old putty or caulk and reapply fresh material. This gives you a watertight seal.

4. Swap Out Supply Lines‍

If the water supply hoses look old or corroded, replace them. Go with braided stainless-steel hoses for peace of mind.

5. Call Fisher & Son’s Plumbing‍

If the leak continues after basic fixes, or if you notice water damage, it’s time to call a licensed plumber. Hidden leaks can cause major damage behind the walls and under the floor.

Signs You Need Professional Plumbing Help

Not every kitchen sink leaking issue can be handled with a wrench and some putty. Watch out for these red flags:

• Constant leaks even after tightening connections. That means something deeper is wrong with the pipes.
• Water stains or swelling in cabinets. This suggests the leak has been going on longer than you thought.
• Moldy or musty smell. Leaks often create the perfect environment for mold growth.
• Sudden spike in your water bill. A hidden leak can waste gallons of water every day.

Why Choose Fisher & Son’s Plumbing?

Leaks can start small but lead to big headaches. At Fisher & Son’s Plumbing, we’ve built our reputation on quick, reliable plumbing service for homeowners along the Mississippi Gulf Coast. We handle everything from a simple kitchen sink leaking repair to full plumbing installations.

We don’t just fix the problem—we make sure it won’t come back. That means checking the whole plumbing system, using high-quality replacement parts, and standing behind our work.

Contact Fisher & Son’s in Gulf Coast, MS

A kitchen sink leaking can be frustrating, but most issues come from a few common causes: loose drains, cracked pipes, worn gaskets, or bad seals. Some leaks can be tightened or sealed on your own, but when the water won’t stop or damage starts to appear, it’s smart to call the professionals.

Don’t let a small drip ruin your cabinets or flooring. Reach out to the licensed plumbers at Fisher & Son’s Plumbing for expert help. Call us at (228) 342-8885 or visit our Contact Page to schedule service today.

FAQs About Kitchen Sink Leaks

Q: Why is my kitchen sink leaking only when I run water?

A: That usually points to a sink drain leak. The drain assembly or the P-trap under the sink may have a gap, crack, or loose fitting.

Q: How do I know if the pipe under my sink is leaking?

A: Look for water puddles, damp cabinet floors, or visible drips from the P-trap or supply lines.

Q: Can a leaky kitchen sink cause mold?

A: Yes. Even small leaks can create damp conditions where mold grows quickly. Mold can harm both your home and your health.

Q: How much does it cost to fix a kitchen sink leak?

A: The cost depends on the cause. Replacing a gasket or tightening a fitting is inexpensive. Replacing pipes or fixing water damage costs more.

Q: Should I use plumber’s tape on leaks?

A: Plumber’s tape helps seal threaded connections but won’t fix cracks or broken pipes. If you see damage, replacement is the only solution.

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