A sewer gas smell is conditionally an emergency. It is rarely an immediate disaster requiring 911, but it must be taken seriously because it indicates that toxic or flammable gases (like methane and hydrogen sulfide) are escaping your plumbing and entering your living space.
Besides the offensive odor, sewer gas can be hazardous especially over any extended period of time. Methane gas can displace the oxygen especially in a confined space and be deadly. Hydrogen sulfide is also toxic.
Yes, sewer gas can make you sick. It is a toxic mixture of hydrogen sulfide, methane, ammonia, and carbon dioxide. Prolonged inhalation can lead to dangerous side effects, so addressing these odors quickly is highly recommended.
Sewer gas drifting into your home's air for weeks or months could leave an offensive smell behind, even after you've aired your home out thoroughly. If, when you return, you smell sewer gas, open the windows immediately. Methane is explosive and the other components of the gas are toxic at various levels.
The first signs of sewer gas exposure are a distinct rotten egg odor and physical irritation. Prolonged or stronger exposure commonly leads to the following early symptoms:
A single small exposure from which a person recovers quickly is not likely to cause delayed or long-term effects. Moderate exposure can cause residual damage and a serious exposure that causes coma or convulsions may damage the brain and heart.
A sewer gas smell is often a sign of plumbing issues, like a sewage backup in the basement or damaged drains. While it's easy to confuse the smell of sewer gas with a natural gas leak, as both can smell like rotten eggs, natural gas smells a bit more like the spray from a skunk than raw sewage.
Temperature and air pressure changes at night can make septic tank odors more noticeable. Cooler nighttime temperatures can cause gasses in the septic system to contract, pushing them out through vents or cracks. Lower atmospheric pressure allows gasses to escape more easily, creating a stronger odor.
Because natural gas is naturally odorless, utility companies add a chemical called mercaptan, which mimics the smell of a skunk or rotten eggs. However, this pungent sulfur scent is frequently mistaken for everyday household items and environmental issues.
Sewer gas usually enters a house when plumbing drain traps (the U- or P-shaped pipes under sinks, showers, and toilets) dry out, lose their water barrier, or become damaged, allowing foul gases to bypass the system.
Two of the most common warning signs of gas poisoning are dizziness and a dull headache. Because fumes displace oxygen in the blood, they often cause "flu-like" symptoms without a fever, which can rapidly escalate to shortness of breath, nausea, and confusion.
Symptoms from sewage exposure typically appear within 1 to 2 days, though the exact timeframe depends on the specific bacteria or virus involved.
Sewer gas exposure during sleep poses serious risks, as the hydrogen sulfide can cause eye irritation, respiratory issues, and even explosion hazards if concentrations build overnight.
Yes. Sewer gas contains toxic compounds like hydrogen sulfide and methane, which can cause fatigue, drowsiness, dizziness, and headaches. In enclosed areas, methane also displaces oxygen, which causes sleepiness and can quickly lead to unconsciousness if the room is not ventilated.
Adequate ventilation reduces the concentration of sewer gas and accelerates odor dissipation. Open windows and doors to allow fresh air to circulate and decrease the odor. Use exhaust fans in bathrooms, kitchens, and laundry rooms to vent any lingering smells outdoors.
Sewage sickness refers to illnesses caused by exposure to raw sewage, which is loaded with harmful bacteria, viruses, and parasites. The most common symptoms include severe diarrhea, vomiting, nausea, fever, abdominal cramps, and headache. Severity depends on how you were exposed.
The first signs of a gas leak include a distinct sulfur or rotten-egg odor (mercaptan is added to make natural gas detectable), a hissing or roaring sound near gas lines, and physical symptoms like unexplained headaches, nausea, dizziness, or fatigue. Pets may also show early signs of lethargy or breathing issues.
The characteristic "old age smell" is scientifically known as nonenal (or 2-nonenal). It is a chemical compound produced when the skin's natural oils and fatty acids break down and oxidize as we age.
Smelling gas when no leak is present is known medically as phantosmia (an olfactory hallucination). It is often a sign of underlying sinus issues, nerve damage from a recent viral infection (like COVID-19), or a neurological condition.
Yes, sewer gas can catch fire and even cause dangerous explosions. It primarily consists of methane and hydrogen sulfide, which are highly flammable substances produced by the breakdown of organic waste. When these gases mix with air in confined spaces, a single spark or open flame can ignite them.
A sewer gas smell usually comes and goes because of fluctuating factors that allow gas to bypass the plumbing system's defenses. It is typically a sign of a dry drain, a clogged roof vent, or changing weather conditions.
Plumbers recommend starting with a DIY enzyme or baking soda and vinegar flush to break down organic buildup. If that fails, they advise physically scrubbing the drain walls or using commercial enzyme cleaners. If the smell resembles sewage, the pipe’s P-trap may be dry or blocked, requiring professional inspection.
The methane component is less dense than air and tends to rise in structures. Check components of plumbing systems for traps (i.e. curved sections that collect water). Water in traps acts as an airtight seal that blocks the odor.
Common Signs of a Broken Sewer Line
Cigarette smoke and pet urine are widely considered the hardest smells to get rid of in a house. Both contain microscopic, deeply penetrating compounds (thiols and uric acid, respectively) that soak into porous surfaces like drywall, carpets, subflooring, and ceiling tiles, requiring specialized mitigation to eradicate.