How to fix a dried up P-trap?

Author: Carrie Bernhard Sr.  |  Last update: Sunday, January 4, 2026

Slowly pour about a gallon of water into the drain. This will refill the trap and recreate the seal to block sewer gases. For long-term prevention, consider adding a small amount of mineral oil on top of the water in the P-trap.

How to fix a dried out P-trap?

To eliminate odors coming from a dry p-trap, pour half a gallon of water into the trap to restore the barrier. It will prevent the odors from seeping through the drain. Another helpful method is to add a cup of white vinegar bleach to get rid of larvae and slow down the evaporation.

What causes a dry pee trap?

One of the simplest reasons a P-trap might dry out is infrequent use of the fixture. In homes where certain bathrooms or sinks are rarely used—such as in guest rooms or basements—the water in the P-trap can eventually evaporate.

What is a possible consequence of dry plumb traps?

However, when your drain is infrequently used, the water in your P-trap evaporates. At a certain point, the water becomes depleted enough that sewer gases can slip through the pipes into your facility. This is when you start experiencing foul odors, the common symptom of dry drain.

How to fix dry drain smell?

The easiest solution to fix a dry drain is to simply re-fill the trap in the sink with more water. Prevent dry drains from occurring by running water in a drain at least every few months. This includes all drains even ones in fume hoods and on the floor. Hazardous waste must NOT be disposed of down the drain.

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How to get rid of smell from P-trap?

  1. If the smell is coming from a sink that is rarely used, flush your drain to ensure your P-trap is filled with water. ...
  2. For this process, start by pouring a pot of boiling water down the drain.
  3. Next, pour a mixture of one cup baking soda and one cup vinegar into the drain.

How long does it take for a P-trap to dry out?

This can happen for a number of different reasons, but the most common cause is due to evaporation. If you don't run any water down the drain for a long time, the water inside the P-trap will eventually evaporate. It usually takes a month or more before the trap will fully dry out.

How to get water back in P-trap?

This usually happens to a sink or appliance that hasn't been used in a long time. We generally see it in utility sinks or guest bathrooms. When the P-trap dries up there's no water and therefore, no seal. Simply run the water for 10-15 seconds to re-establish a seal and you should be good to go.

Why does my bathroom suddenly smell like sewer?

Common causes of sewer smell in the bathroom can be from a dried-out P-trap, a blocked or damaged vent pipe or sewer pipe, a leaking toilet seal or a build-up of organic matter. Rotten-egg smell is a symptom of both septic gas, which leaks in through the plumbing, and toxic drywall, which off-gasses hydrogen sulphide.

How to tell if a P-trap is bad?

Signs your P-trap may be blocked
  1. Your drain isn't clearing after you've done everything to clear the clogged drain. ...
  2. You smell a foul odor throughout your home. ...
  3. You hear a gurgling noise from the sink or tub.
  4. The water in your toilet seems weak, and the bowl isn't refilling quickly enough after a flush.

How to fix faulty P-trap?

  1. Turn Off the Water Supply. ...
  2. Loosen the Nuts. ...
  3. Remove the Old P-Trap Pipe. ...
  4. Seal the Opening. ...
  5. Look for Signs of Damage. ...
  6. Shop for Replacement Parts. ...
  7. Reassemble the Sink P-Trap. ...
  8. Tighten the Nuts.

How long do p-traps last?

Depending on their condition, P traps tend to last on average around five to 10 years. Yet, it's usually those obvious tell-tale signs that plumbers spot, such as leaks, cracks, and corrosion that signal it's time for a new plumbing trap.

Why does my basement smell like sewage but no leaks?

Strong sewer smells in your basement could indicate the lateral is blocked or broken, causing waste and sewage odors to back up into your basement. But that's the worst-case scenario. Sometimes, a neglected drain is the culprit, in which case a thorough cleaning can blast away odors.

How do you clean a P-trap without removing it?

Pour some baking soda down your drain and then pour boiling water down after. Sometimes this will clear the clog. Use a plunger on your sink drain to try to force the clog out of the trap.

How do I stop my washing machine from smelling like a sewer?

Common causes of a smelly washing machine include a buildup of bacteria, mold or mildew, and even detergent residue. To clean it, run a hot wash cycle with a mixture of baking soda and white vinegar. Then, scrub any residue and run another hot rinse to flush out all the cleaning agents.

What causes an empty P-trap?

Traps can lose their water from too much wind and the air outside of the house, which could be getting into the pipes and may bounce the water out of the bowl.

How to fix a dry P-trap in shower?

How to fix a dry P-trap:
  1. Pour one or two cups of water down the drain and wait an hour.
  2. After an hour, take a look down the drain to make sure you can still see the water.
  3. If the shower barely gets used, pour 4 ounces of mineral or cooking oil down the drain.

How to fix P-trap smell?

Slowly pour about a gallon of water into the drain. This will refill the trap and recreate the seal to block sewer gases. For long-term prevention, consider adding a small amount of mineral oil on top of the water in the P-trap.

Why does my bathroom smell like urine even after cleaning?

Your bathroom may smell like urine from several potential culprits. It could be a lack of ventilation in your bathroom, which causes stagnant odors, or a hidden leak in your toilet. Maybe the grout surrounding the toilet is simply dirty—there are ways to get rid of the smell once you identify the issue.

Can water evaporate from P-trap?

The water in the P-trap can evaporate due to excessively dry air conditions. Oscillation occurs when too much outside air enters the pipe, displacing the water out of the bowl. When something is stuck inside the pipe and absorbs water from the toilet, a P-trap can empty due to capillary action.

How often should you clean a P-trap?

You should clean your P-Trap every one to three months. This will help to ensure that you do not smell any sewer smells in your home. It will also help to ensure that your drainage system runs as it should.

When should you replace P-trap?

If the P-trap is made of metal, inspect it for any signs of rust or deterioration—common issues that afflict older plumbing fittings. Should you encounter water leaks under the sink regularly, it likely means that the integrity of the P-trap has been compromised, necessitating immediate attention.

How do I know if my P-trap is broken?

Is your P-trap working properly? If you detect any foul odors near the P-trap that remind you of a smell similar to rotten eggs, then it means that there is hydrogen sulfide present. This, and other harmful gases, bacteria, and viruses, can get into the house if your plumbing trap has malfunctioned.

What prevents sewer gas from entering the house?

Ensuring all plumbing fixtures are installed and sealed securely can prevent sewer smells. Blocked or clogged drains or vents. Blocked or clogged drains or vents can cause a sewer gas smell by prohibiting proper ventilation and drainage of the plumbing system.

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