Don't Panic! Here's How To Safely Handle a Leaky Pipe Under Your Kitchen Sink

It starts with a few small drips under your kitchen sink that you don't think much of. But soon, you notice a puddle on the floor and the drywall looks darker than before. You turn the tap on and water seems to be leaking from several spots under the sink. Don't panic! Leaky pipes under kitchen sinks are common, but can often be fixed with some DIY troubleshooting.

What To Do If You Have a Leaky Pipe Under Your Kitchen Sink

The first signs of a kitchen sink leak may be subtle, like condensation on the pipes or a musty, mildew smell under the sink. Over time, you'll likely notice water pooling on the floor or bubbling in the paint or drywall below the cabinet. If a leak has been ongoing, the drywall may feel spongy or soft when you press on it. The most obvious sign is seeing water actively dripping from fittings under the sink. If you spot any of these warning signs, take action right away to minimize damage.

Stop The Flow of Water

Before anything else, you need to stop the water supply to prevent the leak from getting worse. In most cases, shutting off the angle stop valves under the sink will take care of this. Check below the shutoff valves and along the wall behind the sink to locate these knobs. Turn them clockwise to shut off the water.

Have some old towels or buckets ready to place under the leaking pipe joint to catch any residual dripping. Stuffing a towel around the leak can also help slow the flow while you address the problem.

Assess Severity Of Leak

Carefully examine where the water is coming from. Small leaks from loose fittings or connections can often be fixed with some DIY adjustments. However, if the leak appears to be coming from a crack or split in the pipe itself, you likely need to call in a professional plumber to avoid major damage.

Also check for any areas with severe water damage, like saturated drywall or insulation. Large amounts of standing water increases the risk for mold growth, which can be a health hazard.

Remove Standing Water

Use old towels or rags to soak up any pools of standing water under and around the sink. It’s important to thoroughly dry the area to prevent mildew and mold growth which can contribute to respiratory issues.

You can speed up drying time and moisture removal by placing a fan or dehumidifier near the sink overnight. In severe cases, you may need to cut away and replace water-damaged drywall.

Make Temporary Repairs

For small leaks at joints or fittings, you may be able to stop the flow temporarily with some simple adjustments. Carefully tighten any loose slip joints that connect the pipes under the sink. Use an adjustable wrench or basin wrench to gently tighten the connections.

Small leaks around the sink drain pipe or garbage disposal can often be stopped by applying plumber's putty around the rim of the drain flange where it meets the sink. Stuff putty into any gaps or cracks and let it fully harden to seal the leak.

Call A Professional Plumber

While minor leaks can become DIY projects, it's best to call in a professional plumber if you have a major pipe leak, burst, or severe water damage under the kitchen sink. They have the expertise and equipment to fully diagnose and repair the issue.

Trying to fix a large leak on your own without proper training could result in injuries, flood damage or making the problem worse. Most plumbers offer emergency leak repair services and will send a technician right away to secure a gushing pipe.

What's Causing Your Kitchen Sink Leak?

To properly fix a leaky pipe under the kitchen sink, it helps to understand what may be causing it. Here are some of the most common reasons you may have water dripping from fittings below your sink.

Corroded or Cracked Pipes

Corrosion inside old galvanized steel, copper and polyvinyl chloride (PVC) pipes leads to cracks and pinhole leaks over time. The minerals in water can slowly erode pipes from the inside. Freezing temperatures can also cause pipes to burst or crack.

Loose Joints and Fittings

The constant vibration from turning the faucet on and off can cause the slip joints connecting pipes under the sink to loosen over time. Compression fitting gaskets also wear out and loosen. This allows water to leak out of the gaps between joints.

Broken Seals

The rubber gasket around the sink drain where the tailpiece connects can become brittle and damaged. This breaks the waterproof seal, allowing leakage. Garbage disposal mounts also use rubber gaskets that need replacement when leaking occurs.

Improper Installation

If pipes were connected together too loosely or fit unevenly when installed, the joints may begin dripping. A misaligned P-trap or use of the wrong size PVC pipe cement or sealant can also result in leaks down the road.

Choosing The Right Materials To Fix a Leaky Pipe

Selecting quality, durable plumbing parts ensures your repair will last without leaks returning. Here are some ideal options to fix a leaky pipe under the kitchen sink.

Common Kitchen Sink Pipe Types

Galvanized steel pipes are susceptible to corrosion over 10-20 years. Copper has long-lasting durability but can be difficult for DIYers to cut and join.

For easiest installation, use plastic piping such as PVC or CPVC that can be quickly cut to length and joined with cement. Choose schedule 40 PVC for best thickness.

Quality Fittings and Connectors

Compression fittings don't require cement and can be disassembled later if needed. Flexible PVC connectors between sink tailpieces and trap adapters compensate for misaligned joints.

Use a metal brace or strap to support the horizontal P-trap and prevent sagging. This keeps drain alignments tight and leak-free.

Proper Pipe Sealants

Plumber's putty seals the sink drain flange to the sink basin. It stays pliable to prevent cracking. PTFE thread seal tape or pipe joint compound lubricates and seals pipe thread connections.

Clear silicone sealant safe for drinking water provides maximum adhesion for joining plastic pipes and fittings. Let sealant fully cure before using the sink.

Step-By-Step Guide To Repair a Leaky Pipe Under Kitchen Sink

Once you've addressed any immediate water damage and determined the leak's cause, you can move on to permanently repairing the pipe. Follow these steps to fix that leaky pipe for good.

Prep The Area

Remove everything from under the sink and lay down some towels or a plastic sheet to catch drips. Have your bucket ready to catch water when you unhook pipes. Make sure your wrenches, pliers, replacement parts and other tools are easily reachable.

Shut Off Water Supply

Locate the angle stop valves below the sink and turn them clockwise to shut off the hot and cold water lines. Turn on the faucet briefly to release pressure and drain any water from the pipes.

Disassemble Pipe Joints

Use a basin wrench to disconnect the slip joints linking the sink tailpieces to the P-trap bend. Unscrew the compression nuts attaching the trap bend to the drain pipe.

Remove the P-trap completely and set aside. Also detach the drain tailpiece from the sink drain bottom.

Replace Pipe Section

Inspect pipes and fittings for cracks, corrosion or damage. Measure and mark the section needing replacement. Use a hacksaw for metal pipe or pipe cutter for plastic to remove the bad section.

Install new pipe of the same material using proper connectors. Make sure replacement parts match the exact size of the original pipes.

Reseal Connections

Replace any worn out gaskets and reapply fresh plumber's putty or silicone sealant on joints. Use PTFE tape on threaded connections. Hand tighten fittings first then finish with a wrench.

Test Repair and Restore

With all the fittings reattached and tightened, slowly turn the water back on. Thoroughly check for leaks as water pressure returns. Give sealants time to fully cure before running the sink.

Once you've confirmed your repair is leak-free, you can replace items under the sink and enjoy your drip-free kitchen once again!

While many kitchen sink leaks and drips can be DIY fixes, there are certain cases where you need to bring in an experienced plumber:

• Major pipe leaks or bursts causing water to spray out
• Unsure of the exact location or cause of the leak
• Leak occurring in difficult to reach areas under sink
• Significant water damage or mold growth
• Corroded galvanized pipes needing full replacement
• No improvement after several repair attempts

A licensed plumber has the specialized tools, parts and skills to fully diagnose and tackle repairs you may not be equipped for. For major pipe issues, the cost of professional repair will likely be less than extensive water damage if left unaddressed.

Dealing with a leaky pipe under the kitchen sink can be frustrating. But in many cases, you can stop the flow of water and make repairs yourself without needing to replace the entire sink plumbing system. Focus on locating the exact source, drying up standing water, and using quality fittings to seal joints. And know when it's safest to call in backup from a professional plumber for the big leaks.