How to clean a sink P-trap

The U-shaped trap under a sink catches hair, grease and small objects. Cleaning it clears many slow drains and recovers dropped rings.

What you need

• A bucket and old towels
• Gloves
• Channel-lock pliers, only if the nuts are too tight by hand
• An old toothbrush or bottle brush

Step by step

1. Place the bucket under the trap.
2. Loosen the two slip nuts that hold the trap in place.
3. Remove the trap and empty it into the bucket.
4. Clean the inside with the brush and hot water in another sink, not the one you disconnected.
5. Check the slip nut washers and replace any that are worn or flattened.
6. Reinstall the trap and tighten the nuts hand-tight, then a little more.
7. Run water and check for drips.

If the drain is still slow

The clog is further in, in the pipe behind the wall. With the trap off, a small hand snake can reach it. See our kitchen sink backing up into the other sink guide for double sinks.

Replace the trap if

• It is cracked or corroded
• Metal traps have thin or rusted walls
• It leaks after new washers

Metal or plastic trap?

Older homes may have chrome-plated brass traps, which corrode and can crumble when loosened. Plastic traps are inexpensive, easy to install and do not corrode. If a metal trap is thin or rusted, replacing it with plastic is a common, simple upgrade.