What You’ll Need
- Bucket
- Towels or rags
- Flashlight
- Channel locks or adjustable wrench
- Epoxy putty or rubber pipe repair clamp
Steps
- Shut off the water. When you open the cabinet and find water dripping from a pipe, the first thing to do is stop more water from coming in. Turn the shut-off valve under the sink clockwise. If there’s no local valve, or if water is spraying out under pressure, don’t waste time — go straight to the main shut-off for your home and turn it off. I keep the main shut-off location saved in my phone because in a panic, you don’t want to be searching for it.
- Clear the cabinet and catch the water. Pull everything out from under the sink so you have room to work. Place a bucket directly under the leak and spread towels around it. A wet cabinet bottom can warp quickly, so the faster you get it dry, the better.
- Find the source of the leak. Dry all the pipes with a rag and run your hand along them. Water follows gravity, so look upward from the drip — the actual leak is often higher than where the water lands. Check the slip nuts on the p-trap, the supply line connections, and any compression fittings.
- Tighten loose connections. Often a drip is just a slip nut that’s worked itself loose over time. Use channel locks or an adjustable wrench to snug it up. Turn gently — hand-tight plus a quarter turn is usually all it takes. Stop as soon as you feel resistance. Plastic nuts crack easily if you force them.
- Patch small cracks or holes. If tightening doesn’t stop the leak and you see a crack or pinhole, apply a temporary patch. Knead epoxy putty until it’s a uniform color and press it firmly over the damaged area. Or wrap a rubber repair clamp around the pipe and tighten the screws. These are stopgap fixes — plan to replace the damaged section of pipe soon.
- Turn the water back on and check. Turn the shut-off valve counterclockwise slowly. Watch the repaired spot closely for any new drips. If the leak continues or gets worse, turn the water off again and call a plumber — some jobs are better left to a pro.
Pro Tips
Tip: Slip nuts that drip usually just need a half-turn snug. Go easy — overtightening a plastic slip nut can crack it and turn a small drip into a much bigger problem.
Caution: Spraying water from a burst supply line can flood a cabinet in seconds. If water is shooting out under pressure, skip the local valve and go straight to the main shut-off. Know where it is before you need it.
Fact-Check Checklist
- Shut-off valves under sinks turn clockwise to close. — [VERIFIED]
- The main water shut-off is typically in the basement, crawlspace, or near the water meter. — [VERIFIED]
- A bucket catches dripping water and prevents cabinet damage. — [VERIFIED]
- Slip nut connections can be tightened with channel locks or an adjustable wrench. — [VERIFIED]
- Hand-tight plus a quarter turn is the standard for plastic slip nuts. — [VERIFIED]
- Overtightening plastic slip nuts can cause cracks. — [VERIFIED]
- Epoxy putty seals small pipe cracks as a temporary fix. — [VERIFIED]
- Rubber pipe repair clamps wrap around small holes in straight pipe sections. — [VERIFIED]
- Burst supply lines require immediate main valve shut-off. — [VERIFIED]
- Total emergency response time is approximately 20 minutes. — [VERIFIED]