How to Get Rid Of Sewer Smell in Bathroom Sink

When your bathroom sink stinks like sewer, then something must be wrong down the drain. How to Get Rid Of Sewer Smell in Bathroom SinkThe smell could result from escaping sewer gases or clogs that may be trapped in the P-trap.

The best approach for sewer odor from the bathroom sink is to remove accumulated clogs and ensure the P-trap is functioning properly.

Here’s a guide on how to get rid of sewer smell in bathroom sink.

Related: Garbage Disposal Making Bad Sound

Where Does the Sewer Smell Come From?

1. Sewer Gases

Sewer odor in the bathroom sink usually results when the P-trap is empty or there’s insufficient water to block escaping gases. A P-trap can lose its water when it has a leakage or when the sink has not been used for long time.

The trap can also become empty when there’s a fault in the plumbing ventilation. The plumbing vent aids in maintaining equal pressure on either side of the P-trap. However, improper ventilation results in unequal pressure thus causing suction on either side of the trap.

This leaves the P-trap with little or no water thus causing sewer gases to go up through the tailpiece and end up in your rooms.

2. Accumulated Clogs

Although the bathroom sink is not subjected to too much waste debris, it can accumulate makeup hair, soap scum, crusted toothpaste and dead skin. When they rot, these clogs can leave your sink smelling like sewer.

How to Get Rid Of Sewer Smell in Bathroom Sink

Is the Vent Blocked?

The fact that you’ve not experienced sewer-like smell from your sink before indicates that the vent system was installed properly. If the sewer-like smell persists after cleaning the bathroom sink drain, then the problem could be in the ventilation pipe.

Signs that the drain Vent is Blocked

The entire drain piping system is intended to have neutral pressure within itself. Not only does this allow free flow of waste materials but it also prevents resurgent of sewer-like smells into your sinks, bathtubs and toilets.

A blocked drain vent is usually characterized by the following signs.

1. Sewer Smell

A blocked vent leads to pressure imbalances within the drain piping. The differences in pressure on either side of the sink P-trap allows air to escape through the tailpiece and end up in your bathroom or kitchen sinks.

2. Gurgling Sound

Usually the bathroom sink and bathtub are served by a common vent. If the drain vent is blocked, then your bathroom sink is likely to produce a gurgling sound when you drain the bath tub.

3. Slow Draining

When you notice that the sink is draining slowly, then this could be a sign of surging pressure due to a blocked vent.

How to Unblock a Drain Vent

Usually drain vents are blocked by stuff that enters the pipe from the roof. It could be tree leaves/flowers, birds/rodent carcasses, tennis balls and so on. The best remedy for such vent issues is to remove blockage from the pipe popping out on your room.

You’ll need a plumber’s drain snake to retrieve substances that are lodged deep in the vent. Otherwise, you’ll require the services of a professional plumber.

If you’ve the right tools and aren’t afraid of heights, then follow these steps to remove the substance blocking the vent.

  • Climb up the roof using a ladder whose feet are secured with a rope to avoid accidental slippage. Carry with you a garden hose and screwdriver for opening the vent cap in case it has one. The garden hose should have a nozzle and already turned on from the source.
  • With the help of flashlight you can inside the vent and remove whatever items you can reach with your hands.
  • With the nozzle set to high pressure, insert it in the vent and press the trigger. If debris inside there can’t resist the pressure from the water, they’ll be pushed further into the vent and then into the drain.
  • If the debris have accumulated for long they might not move and water will start backing up. Now, get the drain snake while leaving the garden hose up there. Plunge the snake’s head into the vent and rotate the crank.
  • If you get some resistance, then the auger has caught something inside there. Now retract the auger to pull out the debris out of the vent. One or a few attempts should unblock the vent.
  • When the water in the vent starts draining, then it has got a way into the drain. Now you can use the garden hose again to push the remaining debris into the drain. If water does not back up, then your job is done.

How to Clean Bathroom Sink Drain

Step #1 – Clean the P-Trap

Over time substances may stick on the P-trap and no amount of flushing can push it further into the drain. Removing debris from the P-trap will not only eliminate smells but it will also prevent a major clog.

Opening the P-trap for cleaning isn’t necessarily a handyman’s job. You can do it yourself at home with simple guidelines.

What you need:

  • Pipe wrench
  • Flexible pipe brush
  • Bucket
  • Rags or old towel
  • Hanger wire


  • Place the bucket directly underneath the P-trap to collect water and debris when you disconnect the joints.
  • Using the pipe wrench, loosen the two slip nuts securing the P-trap to the tailpiece and drain. You’ll have to bear with the stench from the old clog once you open the trap.
  • Once the trap is disconnected, lower it in the bucket slowly to avoid spilling the smelly contents on the floor. Keep the gaskets safely since you’ll need them during reassembling. If the gaskets are worn out or have become hardened, you can replace them with new ones from your local plumbing outlet.
  • Using a hooked wire, pull out as much of the trapped residue as possible. Scrub the trap using a flexible wire brush. During scrubbing, use some baking soda and vinegar so that it cut through the grease and kill bacteria. Once you’re done scrubbing, rinse the trap with clean water.

Step #2 – Remove the Pop-Up Stopper

Although a pop-up stopper gives you the convenience of retaining water in the sink basin, it is likely to trap debris such as hair. If your bathroom sink comes with a pop-up stopper, then there’s a chance it’s packed with rotting debris. Follow these steps to remove and clean the pop-up stopper.

  • Remove the pivot rod by unscrewing the nut that connects it to the tailpiece. This is meant to release the plastic channel inside the tailpiece.
  • Now unscrew the pop-up stopper and pull the plastic piece from the drain opening.
  • Pull out accumulated debris using your hands and hooked wire.
  • Scrub inside the drain opening using dish soap detergent and pipe brush to remove accumulated grease. Also clean and disinfect the plastic channel.
  • Return the plastic piece in the drain opening and insert the pivot rod to lock it in place. Screw the pop-up stopper.

Step #3 – Clean the Drain Stub Out

There’s a possibility of debris to clog on the drain stub out (the pipe entering the wall). So, it would be good to clear out the clog in this area when doing major drain maintenance.

  • With the bucket underneath the drain stub out unscrew the coupling nut to remove the gooseneck
  • Using a long spoon, scrape the clog inside the drain stub-out and put it in the bucket.
  • Clean the opening and gooseneck using dish soap and pipe brush.
  • Reconnect the gooseneck and fasten the coupling nut. Remember to insert the gasket.

Step #4 – Reconnect the P-Trap

Now install the P-trap back and fasten the coupling nuts.


When your kitchen sink smells like sewer, then there must be wrong down the drain or the vent. A blockage in the vent is likely to be accompanied by a gurgling sound in the drains that are connected to the sink when you drain the sink.

If there’s no problem in the vent, then you need to clean the sink drain to remove accumulated clogs.

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