Sewer Odor Solutions in Seattle, WA

Jim Dandy Sewer & Plumbing

One major issue we specialize in is sewer gas smells

If you are experiencing a strong sewer gas smell, give Jim Dandy a call immediately, as it can be a threat to you and your family's health. If you smell rotten eggs or sewer gas in your home or business it is a sign of a plumbing problem. Sewer gas can be potentially dangerous.

Bad Smells

Foul Smells

What exactly is the foul smell in your home? It is hydrogen sulfide, which is a gas that comes from decaying organic matter, also known as sewage. Ammonia may be formed in rare cases. Studies have shown that hydrogen sulfide has a depressant effect on the central nervous system in concentrations above 150 ppm (parts per million). Hydrogen sulfide content can be detected by human olfactory senses in concentrations as low as parts per billion. Sewer gases are of concern because of their odor, health effects, and potential for creating a fire or explosions. However, high concentrations of hydrogen sulfide produce olfactory fatigue, which causes the scent to become undetectable. At higher concentrations, hydrogen sulfide can cause loss of consciousness or even death. Sewer gas smells are no joke and are not something to take lightly. If you have a home or business in Seattle, WA and you have detected bad odors, call a professional plumber immediately call Jim Dandy.

Below are possible causes for the sewer smell that you are experiencing:

  • A dry trap
  • A clogged drain
  • A backed up or too short vent pipe
  • Sewer backup
  • Loose fitting pipe connections
  • An old toilet wax ring
  • Leaks from rotted or cracked drain pipes.

Our Staff

Jim Dandy can fix any and all of these issues.

How exactly does sewer gas get into your house? If there is a dry trap in a drain line that is not often used, the water in the trap could potentially evaporate, which ends up breaking the trap seal. If the trap is damaged or cracked and allows the water to run out, the trap seal is lost again. If the drain line is cracked or broken between the main sewer and the trap, there is nothing to delay the flow of gases through the break or crack within the line. If you have a damaged or plugged vent, and it has an untrapped opening in your house, gases may escape through that opening. In order to keep the odors out of a house, call an experienced plumber. Jim Dandy will be able to find the issue within the system and offer the correct ways in which to fix it in the most efficient and cost-effective way possible.

Hydrogen sulfide is strongest near the floor or ground because of the fact that it is a heavy gas. Sewer gas is typically denser than atmospheric gases and may accumulate in basements. However, they may eventually mix with surrounding areas. Exposure to sewer gas can also happen if the gas seeps in via a leaking plumbing drain or vent pipe, or even through cracks in a building's foundation.

Extended exposure to sewer gas can cause:

  • Fatigue
  • Headaches
  • Dizziness
  • Loss of appetite
  • Irritability
  • Sinus infections
  • Poor memory
  • Bronchitis Pneumonia

Sewer gas consists of varying levels of toxic and non-toxic gases depending on the source. Exposure to high concentrations of hydrogen sulfide sometimes causes people to experience a loss of sense of smell. Sewer gas can be fatal at extremely high levels, which contains methane. Methane decreases the amount of oxygen in the air and can lead to suffocation. What happens when someone is suffering from symptoms due to sewer gas or hydrogen sulfide. They are treated with supplemental oxygen, nitrite therapy, or aerosolized bronchodilators. This aims to support compromised respiratory and cardiovascular functions. The dangers of breathing sewer gas are hydrogen sulfide poisoning and asphyxiation. If you inhale very high levels of hydrogen sulfide it can lead to immediate loss of consciousness or even death.

Sources of the problem

Depending on the sewer gas source and other factors such as building and weather conditions and humidity in Seattle, WA, mold spores may also be present in sewer gases. Sometimes the plumbing fixture may not be properly vented if a sewer gas smell is particularly at one or more plumbing drains. If the drain or fixture makes a gurgling noise, the fixture may not be well vented or even vented at all. Plumbing vent piping defects may cause drain noises or may even release dangerous sewer gas odors indoors.

Troubles and mistaken sewer gas odor sources along the way to finding a plumbing vent sewer gas leak problem include:

  • Suspicions of a chimney problem
  • Confusion about odor and plumbing error responsibility
  • A red tagged gas-fired heating furnace
  • Suspecting odors traveling through heating air ducts
  • Visual discovery of open plumbing vents.

Dry Traps

The source of the sewer gas can be plumbing fixtures whose traps have gone dry or have lost enough water that the water seal within the trap has broken. If any plumbing fixture within your home gets used infrequently, run the water or flush the toilet(s) occasionally. Once every three weeks to a month is recommended. This keeps all the P traps working properly. The source of the sewer gas can be plumbing fixtures whose traps have gone dry or have lost enough water that the water seal within the trap has broken.


"Backdrafting" refers to indoor conditions that create sufficient negative air pressure inside a building such that gases may be drawn into the building from a plumbing drain system or such that heating appliances may lack adequate combustion air and may produce dangerous carbon monoxide. Backdrafting in a building can be dangerous. Intake of explosive methane gases from a sewer system or potentially fatal carbon monoxide gas hazards from heating appliances. The factors listed below can create negative air pressure inside a building.


Kitchen or Bathroom Exhaust Fans

These create negative air pressure in those rooms to exhaust the bathroom or cooking odors. Doors that are open between a basement and upper building areas. This may provide a path for basement or crawl space air and odors to pass to upper building levels. Exhaust only ventilation systems in buildings. This can create backdrafting conditions, especially in tighter buildings in Seattle, WA. Fireplaces when in use particularly open fireplaces that do not include an airtight glass fire screen or door.

Rain, wet weather, and local flooding

Extremely humid weather in Seattle, Wa can cause sewer gases to back up through building drains, moving up through building vent piping to above the building roof, or moving into the building through dry traps and drains. Sewer gas reentry into buildings can occur when a plumbing vent is improperly located too close to a window, door, vent, or even a bath or kitchen vent duct. Warm air rising in a multi-story building by natural convection during cold weather creates negative air pressure on lower floors, which potentially draws sewer gases out of dry traps, drains, or faulty plumbing vent piping. Whole house ventilation exhaust fans create very powerful negative air pressure in buildings sufficient to cause backdrafting affecting both plumbing system drain/waste/vent piping and heating appliances. Windows open on upper building floors and closed on lower building floors increase air movement upwards in buildings.

Vent Pipe Cracks

One important thing to know is that vent pipe cracks can leak vast amounts of sewer gas. Plumbing vent pipes that are clogged can also be a cause of sewer gas problems. This can happen in old homes in Seattle, WA where a cast iron vent pipe gets clogged by rust over the years that falls off the inside of the pipe and clogs a ninety-degree bend in the pipe. When a vent pipe is clogged, the replacement air needed by the system will get sucked into the pipes through a plumbing fixture inside the house. When a large amount of water is placed into the drain pipes by a toilet or a powerful washing machine pump, it can readily suck the water out of a nearby bathtub trap or even a kitchen sink trap. Once this happens, sewer gas immediately enters the room through the dry fixture trap.