Why do I only smell sewer gas at night?

Author: Dejah Schuppe Sr.  |  Last update: Monday, May 25, 2026

One of the most common issues of drain odor is due to blockages and clogs. Any type of blockages, whether they are partial or full, can prevent waste water from properly leaving your home. Over time, this stagnant water sitting in the pipes can build up bacteria and produce pungent odors throughout the night.

Why does sewer gas smell come and go?

Sewer odor can come from a trap that has dried out or has been siphoned out due to improper vent piping. Sounds like the smell goes away after you start using the fixtures? This can also be caused by a broken vent pipe. A broken vent can be difficult to find since it could be buried in a wall.

Why do I smell sewage only at night?

Ventilation Issues: Poor ventilation can cause sewer gases to build up, especially during the night when outdoor temperatures drop. This can create a pressure differential that draws gases in from the sewer system. Clogged Drains: A blockage in your plumbing can cause waste to stagnate, leading to unpleasant odors.

Why does my house smell like gas at night?

  • Gas Leak : The most common cause is a leak in the gas line or a gas appliance (like a stove, furnace, or water heater).
  • Faulty Appliances : Malfunctioning or improperly installed gas appliances can produce gas odors.
  • Pilot Light Issues
  • Ventilation Problems
  • Gas Meter Issues

Why does my house smell like rotten eggs only at night?

Rotten Eggs smell? This smell is probably septic gas, unless you have a carton of eggs hiding in your living room. Septic gas has a strong, naturally occurring odor that smells like rotten eggs. The smell is hydrogen sulfide, which comes from sewage and indicates a potential issue with your plumbing.

What to Do If You Smell Sewer Gas

Why does my house smell weird only at night?

Any type of blockages, whether they are partial or full, can prevent waste water from properly leaving your home. Over time, this stagnant water sitting in the pipes can build up bacteria and produce pungent odors throughout the night.

How to find where sewer smell is coming from?

Consider everything that ends up in your drains, especially if you use a lot of products and have a lot of family members using your drains. Other causes of sewer gas odors in your home include a dry P-trap, a loose toilet, or a clogged drain. Another cause of sewer gas could be blocked or clogged vent pipes.

Why do I have very smelly gas at night?

Food intolerance is a very common cause of bad odor flatulence. Typical conditions that can cause smelly flatulence include lactose and gluten intolerances. In both of these conditions, the body's inability to break down lactose or gluten causes smelly gas to build up and eventually be released.

Would a gas leak smell come and go?

Natural gas leaks are particularly likely to cause smells in small, enclosed areas where gas can build up. If the leak is outside, the smell may seem to come and go as the breeze blows it away. The other big sign to look out for is a strange noise.

Who to call for sewer gas smell?

Sewer gas produces a very distinct rotten egg smell, caused when organic materials break down and decompose to form hydrogen sulfide. If you're unsure about the smell coming from your drains or sewers, call a licensed plumber who can perform an inspection or clear and clean blockages.

Is it safe to stay in a house that smells like sewer?

Answer: Only under extremely unusual circumstances. Although hydrogen sulfide is a toxic gas, it will not harm people at the concentrations that exist in a house with sewer gas odor problems. Studies have shown that hydrogen sulfide has a depressant effect on the central nervous system in concentrations above 150 ppm.

Is there a sewer gas detector?

A Sewer Gas Detector is a electronic handheld device that has a gooseneck with a sensor. The sensor detectors sewer gas coming from your drain in your shower, bathroom or kitchen.

How to eliminate sewer gas odor?

Regularly clean your drains using a mixture of baking soda and vinegar or a cleaning solution recommended by a professional. Flush the drains with hot water to help remove any residual odor-causing substances.

Why does my house smell like sewage at night?

There are many things that can make your house smell like sewage. But the main source, outside of something major like a gas leak, is the plumbing fixtures inside your home. Another cause could be a septic blockage or even a frozen septic tank.

Why does my drain smell like sewage but no blockage?

Mould Formation – Mould or mildew forms inside the pipes when there is a leak and water remains standing for a while. The mould can generate a stinking odour that you can smell even from behind a wall. Plumbing Issues – Sewer smell can also be caused due to incorrect plumbing fixtures.

What are the symptoms of sewer gas poisoning?

Irritated eyes, nose, throat, and respiratory system, including tearing of eyes, cough, or shortness of breath. Effects may be delayed. Severe eye and respiratory irritation such as coughing and difficulty breathing. These symptoms may be accompanied by headache, dizziness, nausea, vomiting, and more.

What if I smell gas but no leak?

If your home smells like gas, but there's no apparent leak, here are steps you should follow: Ventilate the house by opening all windows and turning on ceiling fans. After this, if the smell is persistent, evacuate your home. Put out any materials that can create a flame or cause a spark, such as any open flames.

How long can you stay in a house with a gas leak?

If you notice any sign that you have a gas leak, exit your home and call a professional to inspect your system ASAP. If you have a carbon monoxide leak, you could lose consciousness in just 3 hours so it's important to act fast. You might first think to call your utility company but all they can do is cut off your gas.

Will a carbon monoxide detector detect a gas leak?

No, carbon monoxide (CO) alarms cannot detect natural gas leaks. They are designed to detect the presence of carbon monoxide, a poisonous gas formed during incomplete combustion of fuels like oil, gas, propane, and wood.

What to do if you smell gas in the middle of the night?

What to Do if You Smell Gas
  1. DO leave the home, building, or area of the suspected leak. ...
  2. After leaving your home, DO call the 24-hour emergency number for Peoples at 1-800-400-4271, or call your local emergency response number.
  3. DO call 911 to notify police and fire officials.
  4. DO warn others to stay out of the area.

Why does gas get bad at night?

People may experience gas at night due to eating close to bedtime. Specifically, lying down very soon after eating may cause indigestion, which can produce gas. People with irritable bowel syndrome (IBS) may also find that certain foods trigger their symptoms.

Can sewer smell come and go?

Due to the frequent movement of water and waste through your plumbing system, and the varying use of different drains throughout the day, some issues can fluctuate. This means that you may only notice the symptoms of a problem, like a sewage smell, at certain times of the day or in response to certain action.

How to tell the difference between a gas leak and sewer smell?

The first thing is to make sure the smell is sewer gas which is usually a rotten egg smell and not a natural gas smell which usually smells like a skunk.

Where is the sewer vent located?

But there's another part of your plumbing system that can become blocked: your sewer vents. Located on the roof, these vent pipes allow gases to escape from your sewer system. They regulate the air pressure in your system, allowing waste to flow freely.

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