The short answer
Shut off the Water
Turn the shutoff valves under the sink clockwise until they stop. These valves are usually on the hot and cold supply lines. If they are stuck or missing, turn off the main water valve for your home. Knowing where the main valve is before an emergency helps.
After the water is off, open the faucet to release pressure and drain the lines. Place a bucket or towel under the pipes to catch any remaining water. This step prevents further water damage while you work.
Find the Leak Point
Dry the pipes and fittings with a cloth, then inspect them closely. Common leak points are the slip nuts where pipes connect, the drain trap, and the supply line connections. Run your hand along the pipes to feel for moisture that might not be visible.
Look for cracks, corrosion, or worn washers. A slow drip often comes from a loose nut, while a steady stream suggests a cracked pipe. The leak's location determines the fix you need.
- Loose slip nut on the P-trap
- Worn washer inside a supply line nut
- Crack in a PVC or metal pipe
- Corroded metal fitting
- Damaged rubber gasket at the drain flange
- Pinhole leak in a copper supply line
Quick Fixes You Can Try
For a loose nut, tighten it with a wrench, but do not overtighten. If the leak is from a supply line connection, remove the nut and check the washer. A cracked or flattened washer can be replaced with a new one from a hardware store.
For small cracks in PVC pipes, you can apply epoxy putty or use plumber's tape as a temporary patch. These fixes buy time, but they are not permanent. A plumber should replace the damaged section properly.
When to Call a Plumber
If the leak persists after tightening or patching, call a plumber. A plumber can replace worn parts, repair cracked pipes, and ensure the connections are secure. Do not ignore a leak, as water can damage cabinets and subfloors.
If the leak is behind the wall or under the floor, a plumber may need to cut into the wall or flooring. In that case, water damage cleanup might also be necessary. Local water damage pros can handle the drying and repair after the pipe is fixed.
- Leak continues after tightening
- Pipe is visibly cracked or corroded
- Water is seeping into the cabinet base
- You notice a musty smell or mold
- The leak is behind a wall or under the floor
Prevent Future Leaks
Check the pipes under your sink every few months for signs of moisture or corrosion. Tighten any loose fittings gently and replace worn washers before they fail. In Rockwall's humid climate, humidity can speed up corrosion, so keep the area dry.
Avoid using chemical drain cleaners, which can damage pipes over time. Instead, use a plunger or a drain snake for clogs. If you live in Rockwall, keep your shutoff valve location written down so you can act quickly in an emergency.
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Call Now (469) 698-4610Frequently asked questions
Can I use duct tape to stop a leaking pipe under the sink?
Duct tape is not a reliable fix for water leaks. It may hold for a short time, but water pressure will eventually break through. Use epoxy putty or plumber's tape for a temporary patch, and call a plumber for a lasting repair.
What if the leak is coming from the P-trap?
The P-trap often leaks at the slip nuts. Tighten them gently with a wrench. If the trap itself is cracked, replace it with a new one. A plumber can do this quickly, and it prevents water damage to the cabinet below.
Should I turn off the main water if the shutoff valves are stuck?
Yes, turn off the main water valve for your home if the under-sink valves are stuck. This stops all water flow and prevents further damage. After the repair, consider having a plumber replace the stuck valves.