Checking and Cleaning Your Drain P-Traps

Where to Find Your P-Traps

Every sink, tub, shower and floor drain has a trap. Under kitchen and bathroom sinks, you can see it: a U-shaped bend connected by plastic or metal slip nuts. Tub and shower traps are hidden below the floor, and toilets have a trap built into the bowl. This guide covers the exposed sink traps you can safely service yourself.

Inspecting the Trap

Clear out the cabinet, grab a flashlight and look for:

• Moisture, drips or water stains on the cabinet floor
• White crust or rust around slip nuts and joints
• Cracks in plastic pipe or thin, flaking spots on old chrome or brass
• Loose connections you can wiggle by hand
• A trap that is not shaped correctly, such as an S-shaped bend or a flexible corrugated pipe, which can drain poorly

Cleaning a Sink P-Trap Step by Step

You need a bucket, gloves, a towel and possibly slip-joint pliers. Plan on about 20 minutes the first time.

• Put a bucket or shallow pan under the trap and lay down a towel.
• Wear gloves. Loosen both slip nuts by hand, or with slip-joint pliers wrapped in tape to avoid scratching.
• Lower the U-bend slowly, tipping the water into the bucket.
• Clear out hair, grease and debris with a bottle brush or old toothbrush, then rinse the trap in another sink or outdoors.
• Look into the pipe that goes into the wall. If buildup is visible there, the clog may be further down.
• Check the plastic washers inside each nut. Replace any that are flattened, cracked or missing.
• Reassemble, tightening nuts snug by hand plus a small extra turn. Overtightening cracks plastic.
• Run water for a minute and check every joint for drips with a dry paper towel.

Odors and Dry Traps

A sewer smell from a guest bathroom or basement floor drain often means the trap has dried out from lack of use. Running water for a few seconds refills it. If a sink smells even though the trap holds water, the buildup inside may be the source, or the drain vent may not be working properly. A vent problem often shows up as gurgling or a trap that seems to empty itself.

Safety Notes and When to Call a Pro

If someone has recently used a chemical drain opener, do not open the trap: the trapped water can burn skin and eyes. Old metal traps can be corroded enough to crumble when loosened, so expect to replace them rather than reuse them.

Call a plumber if the trap leaks after reassembly, the pipe going into the wall is cracked or loose, the drain is still slow after cleaning, or odors persist. Our drain unclogging specialists can clear blockages beyond the trap, and trap and vent checks are part of our routine plumbing maintenance. To keep the trap cleaner between checks, use the tips in our strainer guide.