Have you walked into your bathroom and noticed a foul smell coming from the sink or drains? Does it smell like rotten eggs, sulfur or sewer smell? If an odor is coming from your drain or bathroom water, it might be because of sulfur. To be specific, hydrogen sulfide gas creates the unpleasant smell. It is produced because of bacteria and can be in places such as the ground, the sewage, and/or contaminated water and pipes.

Before we go into specifics about various smells we must explain how your house was built.

New Construction Houses (less than 1 year old)

When your house was built, it was plumbed according to plumbing code and pressure tested. Every drain and water pipe is pressure tested by the plumber and then inspected (while under pressure) by the local plumbing inspector. Once it has passed inspection, the rest of your house is built. When the plumber installs the trim (sinks, toilets, water heater etc) it is again tested for water and drain leaks. Water is ran thru every plumbing fixture in the house. After water is ran inside the house, we check the meter to see if there is any movement going thru the meter which would indicate a water leak between the meter and inside the house. If a leak is detected it is repaired. We also check each crawl for any leaks after running the water. After the plumbing trim has been installed and passed an inspection (again by the local plumbing inspector) the rest of your house is completed. Water is ran off and on again multiple times until the day you move in by other trades and the superintendent. If there are any issues before you move in, the plumber is called out to remedy the issue.

Sources of Sewer Smell

If you smell sewage in your home, your first instinct is probably to examine the toilet — that seems like the most logical source of the problem. However, sometimes odors persist even after you have thoroughly cleaned your toilet and bathroom, and air fresheners and fans are not enough to dispel the smell.

When nothing you try makes the odor go away, you are most likely dealing with a more significant issue. Examine the following areas of your home and notice if the smell gets stronger in specific locations — your nose will be your first clue in finding the source of the sewage smell.

Odors From Your Shower Drain

One of the most common sources of a sewage smell is not the toilet — if you notice a foul sewer smell in your bathroom, examine the drain in your shower.

A smelly shower drain typically results from one of two issues: biofilm accumulation or a problem with your P-trap.


When we shower, we use many different products. Body oils, conditioner, shampoo, soap and shaving cream wash down the drain along with natural debris like skin cells and hair. Over time, these substances often accumulate along the P-trap and vertical pipes that run underneath your shower.

This accumulation is called biofilm. As it builds up, biofilm begins to release a sewage smell from bacteria and decomposing debris. The bacteria emit a sticky substance that allows them to cling to the side of your pipes, making them difficult to remove without specialized products.

Eventually, this sewage odor becomes noticeable in the entire bathroom, not just in the shower or bathtub.

How to fix the problem: Typically, eradicating biofilm and the shower drain smells it creates is an easy process that does not require a plumber. To get rid of the odors from your bathroom, you will have to unclog the debris that is feeding the bacteria in the drain.

Make a DIY, all-natural cleaner using baking soda, boiling water and white distilled vinegar. Complete the following steps to strip biofilm from your pipes.

  1. Use a screwdriver to remove the shower drain.
  2. Next, boil between five and 10 quarts of water. Let the water cool to 150 degrees Fahrenheit before slowly pouring it down the shower drain.
  3. Follow the water with one cup of white distilled vinegar.
  4. Immediately after you pour the vinegar, pour half a cup of baking soda down the drain.
  5. After two hours, dump a gallon of hot water into the shower drain.
  6. Finally, run a drain brush through the drain to clear out any remaining debris.

If the sewer gas smell in the bathroom persists after you have cleaned your shower drain, contact a professional plumber to examine your water system.


Another common cause of a sewer gas smell in the house includes a dry P-trap.

The P-trap is a U-shaped pipe designed to trap and hold water. When it is working correctly, a P-trap is supposed to hold enough water to prevent gases and odors from the sewer to creep up your drain.

If you do not use your shower often, the water could merely have evaporated from the P-trap. However, if you frequently turn on your shower and still notice a sewage smell from your drain, it may indicate a more severe problem. For example, your P-trap could leak, preventing it from holding water.

How to fix the problem: A dry P-trap can be easy or difficult to fix, depending on the reason it is dry.

If you do not use your shower often, the water could have evaporated. Fortunately, you can quickly resolve this issue — turn on your shower and let the water run for a few minutes to refill the P-trap. The water should be enough to refill the P-trap and stop sewage gases from leaking into your bathroom. If the smell persists, try pouring a quart of water into every drain in your home, including the sink and the toilet.

Odors From Your Toilet

Typically, you can fix a bad-smelling toilet with a quick clean, a few flushes and some air freshener. However, sometimes a smell will not go away, no matter how many times you clean your bathroom.

There are several potential reasons your bathroom smells like a sewer. Some of the most common include a broken or loose seal or a damaged toilet.


If your toilet smells like sewage, it could have a broken or loose seal.

The toilet attaches to the drain through two different seals. If these seals are loose, broken or improperly installed, they could allow sewer gases to enter your bathroom. One indication of a broken seal is if the toilet bowl does not fill up normally.

If a seal leaks water and sewage, a bad smell might not stem from sewage gases. Sometimes, water will pool in crevices in and around your toilet, attracting bacteria. As the bacteria grow, they produce a foul odor.

Sometimes a toilet leaks from the wax ring, which seals the toilet drain and prevents water leakage. If the toilet bowl is loose, it can damage the wax ring, leading to sewage seeping out and producing bad smells. If you’ve plunged the toilet really aggressively when it was plugged up, you might have blown out the wax seal causing the toilet to leak.

Your toilet could also be broken, cracked or otherwise damaged. For example, it may have cracked around the bolts that fasten it to the floor or from using a drain snake too aggressively. Even small cracks can let sewer gas seep into your bathroom.

How to fix the problem: If the problem is a broken or loose seal, to repair it, reset the toilet with a new toilet ring.

Check to see if your toilet bowl is wobbly or loose — if it is, it may have broken the wax ring. To repair it, reset the toilet with a new toilet ring.

If the toilet itself appears to have broken, contact a professional plumbing service for repairs.

Odors From Your Sink

Sometimes, a sulfur-like smell comes from your bathroom sink.

A stinky sink can have many causes — just like a shower drain, it could have a dry P-trap, for example. However, another common source of odors is buildup in the overflow.


If you notice a sewage smell coming up from your sink, check to see if it has an overflow mechanism.

Many sinks come with a hole near the top designed to provide an outlet for water, preventing overflows from spilling into the bathroom. Like anything near water, your sink can build up grime and mildew quickly, especially in the overflow area.

How to fix the problem: Fortunately, cleaning the overflow is an easy project. All you need is water, bleach and a small bottle brush.

  1. Use a small bottle brush to scrub the interior of the overflow area and remove any debris.
  2. Next, mix a solution of half water and half chlorine bleach.
  3. Using the bottle brush, apply the solution to the overflow area to eliminate any lingering bacteria or odors.

You can also try using Drain-O to flush away the buildup.

If the odors do not go away after a thorough cleaning, contact a professional plumbing service to examine your sink.

Odors From Your Washing Machine

When you notice your house smells like sewage, the first place you look is probably the bathroom. However, if you cannot locate the source of the smell, examine your washing machine — the cause of the problem might be hiding in your laundry room.

The most common causes of a washing machine that smells like sewage are front loading washers that need their filters cleaned out periodically.


P-traps are not just for your bathroom — they are essential for washing machines, too. However, unlike many bathroom pipes, modern washing machines come with a flexible drain hose. The wastewater from a washing machine flows through this flexible hose into the drain box pipe, which connects to the P-trap.

Because the hose is flexible, it can easily be improperly installed. The hose may have been inserted too far into the drainage box, which prevents the P-trap from functioning. As a result, odors can seep into your home.

How to fix the problem: To solve this problem, try pulling the washing machine drain hose out of the drain box. Stop when the hose is roughly eight inches deep in the piping — this will let the P-trap work properly, keeping sewer gases from leaking into the room.


Another common reason for a bad-smelling washing machine is a clog in the drain pipe.

A clog in the drain line will create a buildup of organic matter like hair and soap. Bacteria will form on the clog, creating a nasty odor that resembles the smell of sewage. If left untreated, a clog will build on itself, growing larger and larger and producing more noticeable odors.

How to fix the problem: Fortunately, a clogged drain has an easy fix. Using a drain snake, clear out any clogs in the drain line. If the clog refuses to budge, contact a professional plumber to take a look at your drain and washing machine.

Odors From Your Water

If you notice a sulfur-like smell when you turn on the tap, the problem may go deeper than a clogged drain. Before assuming your water is the problem, try a few troubleshooting measures.

Use a de-clogging solution to eliminate any buildup in the pipes. After you’ve given the cleaning material time to work, pour a glass of water down the drain and walk away from the sink. Smell the water — if it still has an odor, you might have bacteria in your water heater, or your water might contain hydrogen sulfide.


If the smell is only noticeable when you use hot water, the problem is most likely with your water heater.

Occasionally, bacteria colonies can establish themselves in a water heater if the temperature of your heater is too low or if you leave it turned off for long periods. Fortunately, the bacteria should not be harmful to humans, so your health is not in danger. However, the bacteria produce a strong rotten egg smell in the house, which reduces your ability to enjoy your water.

How to fix the problem: If bacteria are thriving in your water heater, you can try increasing the temperature of your heater for up to 24 hours. Run the hot water taps to flush out the pipes of any remaining bacteria.

Remember to proceed carefully if you decide to turn up the temperature of your water heater — it is easy to forget your water is hotter than average, which can lead to burns.


If your water smells bad regardless if it is hot or cold, the problem might lie in your water source. Highly concentrated amounts of hydrogen sulfide produce a strong sulfur smell in the house.

Although hydrogen sulfide can be toxic in large amounts, it is usually easy to detect before it reaches harmful levels. Humans can detect the presence of hydrogen sulfide as low as .5 parts per million (PPM) — levels less than 1 PPM will produce a musty scent, and levels between 1 and 2 PPM will have an odor similar to rotten eggs.

How to fix the problem: If you suspect your water source may contain hydrogen sulfide, contact your local water testing lab to have your water examined for contaminants.