Backdrafting sewage odor Q&A - Set#2

This article series discusses the role of back drafting in buildings, exhaust fans, or other building air movement in causing sewer gas or septic odors (and other building smells and odors). This article is part of our series SEWER GAS ODORS that helps track down and cure the source of sewer gas or septic smells in buildings.

Back-Drafting Sewer Gas Odor FAQs

Questions & answers about the relationship between backdrafting and odors in buildings, posted originally

at BACKDRAFTING & SEWER/SEPTIC ODORS - please check out the diagnosis and cure advice given there.

On 2019-01-08 by Anonymous

Thanks for the advice

On 2019-01-06 by (mod) - Usually rooftop vent gases don't enter a home

Usually rooftop vent gases don't enter a home but are dissipated outdoors. However there are on occasion downdrafts that are site-specific and that can send gases into a building through open windows or, perhaps other openings I can't see on your Michigan home.

You can start by having a plumber pressure test your vent system to be sure it's not leaking.

On 2019-01-06 by Bob J

My family and I recently moved into a home in Michigan. When it is humid, which is often, we get a strong sewer smell outside the home and to a lesser degree inside. Can the gases from our rooftop ventilation pipes get inside the attic/home? What kind of testing would you recommend?

On 2018-11-25 by (mod) - If outdoor odors for example from local skunks are entering your home

Fab

If outdoor odors for example from local skunks are entering your home through the bathroom exhaust vents that I suspect that the vent termination cap is defective, perhaps missing a flapper that normally Falls to close the vent.

On 2018-11-23 by Fabian

Bathrooms in my house will allow odors from the outside to come in, for example when a skunk sprays near my home and I will start to sense the accumulation of their foul smell entering the home so I close all the bathroom doors.

Is there a way to stop foul odors from coming in through the bathroom air vents?

On 2018-10-24 by (mod) - stormwaters that back up

Often stormwaters that back up and enter a property are sewage-contaminated. I'd inspect as needed to rule that out first.

On 2018-10-24 by Tish

After a recent hurricane i noticed my home is starting to smell like sewer gas. Can it be because of the high winds and vent trap on the roof

On 2018-08-01 by (mod) - smell is coming from the camper itself

If the smell is coming from the camper itself, try using a household cleaner or even detergent in warm soapy water to wash the area including what might be your sewer hookup or drain.

On 2018-08-01 by Sammye

We have a sewer smell on the outside of our camper. What do we do? How do we get rid of it.

On 2017-12-29 by (mod) - find a plumber who has drain camera that can scan the piping,

Yes, Kathleen,

You could find a plumber who has drain camera that can scan the piping, or the piping can be pressure tested to confirm it actually leaks - perhaps instead it's becoming blocked by frost?

On 2017-12-29 by Kathleen

We had a laundry room and sink moved from the first floor directly above to the second floor.

Since then whenever the temperature drops in the winter, the entire first floor smells of sewer gas. I have had several people try to find a leak or crack in the vent pipe but since the walls have been closed up not many are willing to put a lot of time into finding the source of the problem. Is there a way to solve this without ripping open the walls?

On 2017-11-26 by (mod) - heck for a loose toilet or a leaky toilet flange

I would check for a loose toilet or a leaky toilet flange that perhaps is leaking sewage effluent into the floor or under the slab. But also check for a missing or inadequate vent on the toilet drain.

On 2017-11-26 by Jodie

Why are we smelling an odor after flushing toilets in the basement. Nothing seems to be clogged. There is no back ups, gurgling, or slow drains. No pooling water or smells outside.

On 2017-07-15 by Jess

My crawl space smells horrible after we have alot of rain. It usually occurs when we run the sump pump. But the waterlevel is high and it smells all the time now what cann be done?

On 2017-06-02 by (mod) re: sewage odors in rainy weather after vent system modified

Sabrina,

we need to get an accurate diagnosis of the cause of the odor before any fix can be attempted.

This article may help you prepare to talk with a plumber:

SEWER GAS ODORS in COLD / WET WEATHER as there we also discuss odors related to conditions that occur in rain or wet weather.

On 2017-06-02 by Sabrina

I just had my bathroom done and they had to repipe the pipe from the toilet to the stack.

So now it raining outside and I'm getting a sewage odor inside my house thats really strong smell. I call the plumber who did it, but can not get a answer. what do I do?

On 2017-05-04 by (mod) re: find the odor source before trying a remedy.

Sharon

You want first to find the odor source. For example if there's been a water leak you'll need to find and fix the leak as well as to remove moldy drywall or insulation. Links at the end of this article suggest where to start.

On 2017-05-04 by Sharon

It really smells in the laundry room but eventually gets all through the house. What can I do to remedy this

On 2017-03-28 by (mod) - re: odors ever since a flood

Brian

As you say there were no odor problems before your area was flooded I suspect that a drain line or septic component has been blocked or partly blocked by sediment or mud brought in by the flooding. Perhaps a vent as clogged too.

On 2017-03-28 by Brian

Ever since our area had a flood every time it rains our basement gets the smell of sewer in our basement, not sure we're to start but is starting to get worse .

On 2017-03-26 by (mod) - re: sewage leaks under a home?

I'd look for a sewer line leak under or near the home, perhaps asking a plumber with a sewer line camera to inspect both the drain piping and the vent piping.

On 2017-03-26 by Greg

Whenever it rains, or we have a Springtime thaw, we have sewer gas smell in the basement of our home. We are connected to the city water system. Would sure like to know how to fix this problem.

On 2017-03-06 by (mod) - re: odors traced to dry plumbing traps

Yes a dry trap can be a source of plumbing odors. If the bath fixtures aren't to be used for a time just pour some clear mineral oil to fill the trap(s).

Water wouldn't evaporate out of a trap in just a few hours, but improper or clogged venting might cause it to siphon out of traps when other fixtures are being drained.

On 2017-03-05 by Holly

The closet was next to a downstairs bathroom and a shower that was hardly ever used.

Plumbers I spoke to suggested the water in the shower trap could have evaporated and I was smelling methane gas due to upstairs bath use. I poured a gallon of water in the shower drain downstairs and then used the upstairs bathroom extensively and then had no smell! No smell for a week. However it rained really badly last night, the bath was used this morning.

The smell in the closet was back. I poured more water into the shower drain downstairs - half an hour later, no smell. Articles I've read suggest that water can be sucked out of a p trap if the vent is blocked. Would you suggest that's my problem?

I'm assuming rain triggers this due to rainfall going into the roof pipe and if it's blocked not draining, causing more of block and not allowing the gas to vent?

On 2017-02-25 by (mod) - re: skunk smells

Holly skunk smells are quite distinctive, though there might be some mold or other odor sources that are similar. I'd look for leaks and I'd inspect the floor framing for mold.

On 2017-02-23 by Holly

I have a two storey townhome and there is a strong skunk odour in the first level closet underneath our stairs that only occurs when it has rained outside in combination with the bathtub upstairs being run. It is very strong but goes away after a day of the bath not being used.

There are no signs of moisture. The three roof vents were replaced 3 weeks ago as there was cracking and one was leaking. However the smell still persists. When it was -10, -20 here there was never a smell even if it snowed.

I have consulted with a roofer and a restoration company and no one knows how to fix it or the source. Do you have any suggestions?

On 2017-02-08 by (mod) - re: when toi inspect the septic tank and plumbing in tracking down an odor

OK then I think the next step is a competent septic system inspection, including conditions in the tank, such as evidence of blockage, sewage passing over baffles, damaged baffles, or improper sewer piping venting.

On 2017-02-08 by Donna

We're in the dry season, we haven't had any rain in months. I wish we did.

On 2017-02-08 by (mod)

Sounds as if your sewer pipe or septic tank are flooding with rainwater.

On 2017-02-08 by Donna

We purchased a home in sw florida 2 years ago . Before the closing the previous owners had a new septic tank installed, no problems everything is great. About 2 months ago i've noticed a poop smell comes in the front bathroom window when it's open.

I never had this problem before. When I close the window it goes away. All the drains work good . There is a vent on the roof, close to the window. I don't understand why it now smells.

On 2017-02-07 by Randy

I have a house built in 1960 and when it rains hard or get more that couple inches of rain, I get a pretty strong sewer smell for a day or two. I have a septic system and leachbed.Could someone give me an idea of where the smell is coming from?

On 2017-02-02 by William

I happened to find this site when I was searching for any available information about sewer odors in home. I hope my questions are posted appropriately. We recently moved into a small townhouse down at south Florida. There is constantly a sewer odor that comes from the kitchen.

I located the source is inside the side wall against which dishwasher and sink are positioned. When I pull away the appliances or open the cabinet below the sink, I could smell strong odors passing through the gap between the drywall and floor.

This air&odor movement becomes more pronounced when the AC is on.

Feels like the air with odor is sucked out from inside the wall. At the same time, at the bathroom on the second floor, a 1 square feet hole was made a few weeks back due to a replacement of faucet fixture. I noticed the same strong odor inside the hole.

This wall and the wall in the kitchen are connected, I believe. Another fact is that the temperature went down below 74 F for the whole last week. The odor disappeared completely. When the temperature raises yesterday above 74 F, the odor comes back again. How should I deal with this odor issue? Thanks for your assistance.

On 2017-01-25 by John

I have a slight smell of sewer gas in my master bathroom. This is usually when it is rainy/foggy. I have no vent in the bathroom. I believe all the traps are good. I have no gurgling or slow drainage.

Am I wrong and a trap is bad? Would there be an atmospheric issue?

The smell seems to come from the toilet and not any other drain. Would the toilet wax seal be leaky or eroded?

On 2016-12-27 by (mod) - re: stormdrain overloads may back up into sewer system

Perhaps an overloaded storm drain was backing up into your sewer line, slowing drainage.

On 2016-12-27 by Chris

During a storm Sunday night, my main bathroom had a minor sewer smell (noticeable but not enough to chase us out of the house). It seemed to come from the bottom of the toilet, that's where it smelled most. So I closed the door and turned off our furnace.

After the storm, once the smell dissipated, it's been fine for two days. This hasn't happened before that I know of. There is no fan in any of the bathrooms. No leaks around the bottom of the toilet. I'm on city sewer. Any ideas?

...

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