Questions & answers about diagnosing cold-weather-related sewer or septic system odors.

This article series describes how to diagnose and correct sewer gas or septic odors (and other building smells and odors with focus on diagnosing odor sources and causes in cold weather.

Sewer Gas Odors in Cold or Wet Weather, FAQs

These questions and answers were posted originally

at SEWER GAS ODORS in COLD / WET WEATHER - be sure to review that article.

On 2021-06-08 by Sam - Odors from cesspool when yard floods

I have a cesspool in my back yard. A while back we had heavy rain for a few weeks. The yard would flood out and than drain off.

About 3 weeks later sewage smells began to appear. I dug out around the pump out inspection cover to inspect the cesspool and found there were cracks around the cover large enough to let sewage overflow out of the cracks.

The cesspool is about 1/2 full if that as we run our grey water into the gardens. Is it possible that the sewage affluent overflowed out of the cover during the heavy rains and saturated the soil when the water table rose.

When digging out the black cast sewer line the soil smelled of sewage and waterlogged soil. No oxygen in soil so the there is that smell also.

As I was digging out the line the soil would smell but not the sand pack around the black cast pipe. Repaired the cesspool cover.

I spread 150 pounds of hydrated lime on the affected area to disinfect the area.

Still have odors that waft up from time to time as the hydrated lime solution did not go very deep. Here is my question. How long do you think it will take for the smell in the soil to go away once things dry out ? Does not smell in the morning or afternoon. Just mid day when there is a breeze.

Running a strong bleach solution down the toilet to see I can smell bleach to let me know if there are hairline cracks in the sewer pipe that I may not have seen.
Thank you for your help.

On 2021-06-09 by inspectapedia.com.moderator - First check cesspool safety; then discuss how long until sewage odor from cesspool overflow goes away?

@Sam,

Watch out: whenever I learn that someone has a cesspool at their property my very first concern is for safety. An unsafe cesspool cover or improper cesspool maintenance (such as pumping a cesspool made of concrete blocks) is far more dangerous than you may realize.

I'm sorry to say I've been consulted in cases involving an ugly death when someone fell into a cesspool after stepping onto an unsafe cover.

So before you do anything else, block off access to the cesspool immediately and then

See details at SEPTIC & CESSPOOL SAFETY 

How long the cesspool overflow odor will last:

I have no facts on which to give an answer with confidence, but in general, if there is a sewage effluent spill on the surface from a single event (not recurrent) then given a month of more-dry weather and no other concurrent problems like a failed cesspool itself, the odor ought to be dissipated.

If the cesspool is full, leaking, or is failing in any way that can cause a surge in odors

Watch out: A properly working cesspool will

- not overflow onto the yard surface under any conditions

- does not flood with rainwater or surface runoff

- has a top sewage level that is 6" or more below the bottom of the inlet pipe to the cesspool (even that means the cesspool is near end of life)

So if your cesspool is flooding, even just occasionally, you will want it inspected

• if in dry weather the cesspool is nowhere full (you say yours is at 50% level) then what is needed is to fix the cause of its flooding in wet weather - correcting surface or roof runoff handling nearby
  
• if the cesspool is nearly filled OR if it is low in dry weather but floods from rising ground-water (as opposed to surface runoff or other leaks that you could repair)
  
  then it is not functional and a new one is needed (often the "new" cesspool is simply daisy-chained downstream from the old one, but if the old one is a flooding source you may not want to do that)

You will want to review

CESSPOOL FAILURE CRITERIA

and also the article above on this very page where we discuss sewage odors in cold or wet weather

let me know what you think and what questions remain; keep me posted

Thank you for the helpful question

On 2021-06-09 by Sam - cracked cover was causing cesspool flooding

Thank you for getting back to me.

The inspection cover for the cesspool had cracked along the cover so when we had flooding rains where the water table raised up in the yard 12 to 18 inches above the soil surface and then drained off when the rain subsided for about a week the liquid sewage slurry must have come out through the cracks. Some cracks were over 2 inches.

Repaired the cover. The cesspool is about 1/3 full if that. Just the toilet and kitchen sink waste water go into the cesspool. Vanity, shower and washer go into the garden. Just 2 of us here.

When digging out the black cast line the soil had a sewage smell but the sand pak a lot drier than the soil with no odor.

Soil strata drainage is excellent Not worried about health hazards as heavily hydrated limed the area and then spread a layer of mulch over the lime. Will plant sunflowers to filter the soil and hope for drier weather. Has been raining every day for months.

Reply by (mod): flooding cesspool is a failing cesspool

If your cesspool is in an area subject to flooding it's not a functional system, regularly discharging sewage into nearby surface areas and if they're close by, streams or lakes; and depending on where you live it may be illegal.

 

On 2021-03-14 by Kimberly - My septic tank is leaking into my yard

My septic tank is leaking into my yard. I've already had it pumped but there is still a foul odor and yard is soggy in that place. And when it rains it smells terrible.It's not leaking at the tank, but it is in my yard. Please tell me what you think is wrong

On 2021-03-14 by (mod) - signs of a clogged or failed drainfield

@Kimberly,

Regardless of whether the leaks are actually right at the septic tank or elsewhere in the yard, unfortunately that sounds like a blocked, clogged, or failed drainfield.

See SEPTIC FAILURE SIGNS

You'll want an onsite inspection by a septic contractor or by an experienced septic test or inspection service (not just a superficial examination), perhaps using a sewer line camera or some small test excavations to find out if the repair is a simple one like a broken or clogged pipe, or if the drainfield needs replacement.

 

On 2021-02-09 by Mary - Terrible smell at a house connected to city sewer

I am connected to a city sewer. It has turn very cold this last week and the smell in the house is terrible. I have run water down all drains but it did not help. What is causing this problem

On 2021-02-09 1 by (mod) - check for trap siphonage due to ice-blocked plumbing vent

Mary,

Thank you for your question. I really want to help and must apologize that with so little information I can't really diagnose what's wrong with the odor problem in your home. You'll need an on-site expert.

In case it helps here is a speculation: It's possible that the problem is indeed cold weather related such as frost accumulation in a plumbing vent that has blocked venting. ]

If your venting is blocked it's possible for water to become siphoned out of the traps found at sinks and showers and bathtubs.

When you lose that water seal the sewer gases easily come up into the building. A quick fixes to make sure that there is water in each of those traps.

On 2020-12-21 by cindy - Strong sewage smell through vents

I was getting strong sewage smells last night. Not from toilets, or sinks, but through the vents. When I went into the furnace/water heating room, the smell was stronger.

Is this an issue with the venting system, water heater or furnace. The smell stopped at about 2am. I haven't smelled it since. Not sure what was going on. It lasted for six hours.

On 2020-12-21 by mod) - possible odor transmission through heating ducts? Urgent safety warning.

Cindy

From just the information in your text I can't say with confidence what's going on in your home.

But it sounds as if you have forced hot air heat in your home and that I know odor was coming out of the heating ducts.

If that's the case I would be looking for an older Source near the return air Inlet or a leak into the ducts themselves.

Is it an "issue" ? Yes.

Watch out: sewer gas is potentially explosive and in any event sewage odors in a building tell us that something is wrong: with the drain/waste/vent system, OR if it's a gas odor there could be a dangerous LP or natural gas leak.

On 2019-04-05 by Red - Odors from neighbor's lagoon septic system

My neighbor started complaining about a sewage smell in her house but could not find the source (she and I both have lagoons)

shortly after her telling me I began to have the same smell in my house. Especially if I started running water in the tub. Is this just coincidental? If not what would be the issue and is it potentially a much bigger problem.

On 2019-04-05 - by (mod) - lagoon septic odors

Red

While some odors are normal from lagoon septics, the smell ought not be apparent simply when running water into a bathtub.

I'd start by asking if the odor is from the drain/waste/vent system or if it's actually from the incoming water supply.

Sniff closer to the water vs the drains.

If it's the water supply, take a look at SULPHUR & SEWER GAS SMELL SOURCES

also this article would be useful: WATER ODOR DIAGNOSIS - SULPHUR

Since you report that both homes use septic lagoon treatment systems, it may be helpful to take a look at

LAGOON SEPTIC MAINTENANCE

On 2018-12-30 by Anonymous - foul sewer odour in our master bathroom

... came across your website while looking online for possible causes of backdrafting. We seem to have a foul sewer odour in our master bathroom from time to time with no particular pattern. But it’s move prevelant when the ground is soaked with rain or snow. We have a septic tank in our backyard.

I’ve had a few plumbers come to look at it but nobody seemed to have a clue. They all made guesses but couldn’t find/fix the problem.

I was wondering if you can come to look at it in Connecticut or if you could recommend what type of professionals I should talk to (roofers, plumbers, others?) to diagnose the problem? If you have any recommendations or names, I’d greatly appreciate it.

Moderator Reply

In addition to a review of the suggestions in the article above on this page,

It would be informative as well to have a septic contractor open your septic tank and inspect the septic tank level during wet weather and when you're observing the odor you describe; if the fields are failing and back-flowing into the tank that could be slowing drains or even pushing higher quantities of sewer gases back up the building drain waste vent (DWV) system;

in that case any indoor piping imperfection, even a loose toilet or bad toilet wax ring, or a dry drain or trap or outdoors downdrafts from the roof can explain a wet or cold weather odor complaint.

Question: neighborhood sewer gas smells

our whole section of town often smells of sewer gas! it is noticeable for 2 or 3 blocks. what's up with that? p.s. - most often is worse when it cools down after a warm day or during the monsoons.. - Sharon 7/22/11

Reply:

Sharon when there is a sewer odor in the neighborhood, if your homes are on private septic systems I suspect someone's drainfield is in failure.

If we're talking about a community where every home is connected to a municipal sewer, there could be a burst line, effluent breakout, a problem with a pumping station, or the odor could be from something else.

Question: cesspool odors that stop when the rain stops - smells during heavy rains

I would like an opinion. I have a cesspool, it has been pumped out even though the gentleman said it did not need it.

Every time we have heavy rains in our area I get a foul smell inside my home;. when the rain stops the odor goes away. I had it pumped thinking that was it but the cesspool man said it was not

Can you give me any idea of what it might be the system was installed in 1964 and even though old still works perfectly with this one exception. Thank you - Carol 8/15/11

Reply:

Carol

Possibly your plumbing vent system is not working properly and/or there are downdrafts from a plumbing vent into or around the home in wet weather;

More likely the cesspool is flooding and forcing sewer gases back into the home, perhaps leaking out around toilet seals or from un-vented or poorly-vented sink or tub traps.

Rain could be flooding the cesspool, causing a breakout of septic effluent and odors - more likely if that were the case the odors would be strongest outdoors at the cesspool; It would be stunning if there were a 1964 cesspool that was still working. In what part of the country/world are you located - what soil conditions?

Question: bad sewer smell early in the morning - landlord says system needs to be broken in

We moved into a doublewide in western NC last March. We noticed, mostly late evenings and early mornings, a really bad sewer smell.

Our landlords said that sometimes, as a system gets used to new people and new system uses, it can be a little smelly. Anyway, soon, spring and then summer arrived and the smell had gone away completely.

At the very first sign of fall, however, the smell has returned. Now that all of our nights are in the 40's or below, we are smelling it again every morning and evening, but not during the heat of the day when temps reach the 70's. There is no smell coming from inside the house, only what drifts in through open windows.

Everything seems to drain fine in the house. Totally clueless and really frustrated at this point. - Jeff 10/6/11

Reply: nonsense!

Jeff,

That's a new one on me - I don't think septic tanks and drainfields know who is using the system.

There might of course be a difference in the level of usage - if the new occupants are using more water or if there are more occupants than previously, that may be causing a septic failure to show up. The fact that you smell odors outside only sounds as if there may be a failing septic drainfield.

Question: smell in unfinished bathroom

I hope that some help be given as we are at our wits end. I have and unfinished bathroom in the basement and we are haven s sewer smell that is very prominent in the unfinished bathroom.

Could this smell be coming from were the fixtures are plumbed but not in stalled I would love some feed back as we are so confused on what to do - Laila 10/20/11

Reply:

Laila

I'm not sure what is the state of affairs in the new bathroom, but here are some possible reasons you'd smell sewer gas there:

1. If you have an open drain line without a trap, such as a mount for a toilet, sewer gases would come out there - use a rubber plug or a large rag to stuff that opening until a toilet is ready to install. Don't let the rag or opening-closer fall down into and clog the pipe however.

2. If you have fixtures like a sink or tub or shower that are installed and have plumbing traps but they have never been used, the trap will be dry and sewer gases can come out at those points.

Just pour some water into each trap to form a seal. A cup or two will be plenty. If you are not going to use the fixtures anytime soon you can pour in clean mineral oil instead.

3. If fixtures were installed improperly you could have a leaky toilet wax ring seal

4. If the plumbing was amateur or incomplete you could be missing a plumbing vent connection or the plumbing vent piping could be incomplete, disconnected, or leaky.

Keep us posted - what you report will help other readers.

Question: sewer odors coming out of interior perimeter drain in dry basement

Ok I have an issue... I own a bi-level home. One of the bedrooms is in the lower level. The entire lower level is finished.

There is a french drain that run around the entire basement, however most of it is covered. There is no water, nor has there ever been any water in the drain. Over the past week, out of the blue the odor that is coming from the drain is mind blowing.

It smells like ammonia and other things. The room that smells is closest to the septic tank. Thinking that there might be a problem I had the tank emptied and still no relief from the smell... When it rains the smell only gets worse... Any suggestions on what I might be looking at. - Brian D 11/29/11

Reply:

Brian, on occasion I've found that a leak in the sewer line or even at the tank itself it it's near the house can leak into the foundation drain or perimeter drain and even enter the basement. As you've not seen a problem at the tank itself I'd check the condition of the sewer line between the house and the septic tank next.

Also, if the building's vent system has become clogged (animal, insects, etc) that could be a source of local smells.

Question: raw sewage odors in very cold weather

I read your article and I would like to explain my problem to see if I have come up with the problem.

I live in Cheyenne Wyoming and when it is very cold (below 25 degrees Far.) we get a very strong raw sewage odor from our basement bathroom. I have narrowed it down to the bathtub. We did not finish the basement, it was finished when we moved in.

The odor was not disclosed to us when we moved in 3 years ago and this winter it is worse but it is colder. We have smelled it every winter since we moved in. Now tonight I decided to try an experiment. I closed the drain on the tub and put water in the tub and this seemed to fix the problem.

So my opinion is that they did not put a "P" trap on the tub. So what do you think?
I do not smell the odor from the sink, the toilet, or the floor drains.
Thank you - John 12/6/11

Reply:

John,

There may be a corroded leaky P-trap that thus doesn't maintain its water seal. Try pouring water into the trap and inspect with a good light to see if it remains in the drain; Unfortunately some demo and digging may be in order to fix this odor source.

Question: septic tank under the garage

Our septic tank is located under our garage we have a sealed hole with a cap on it during the cold months we get a sewer smell in specifically one part of our bathroom its the area where all the pipes are located the toilet shower and sink water all go into the septic tank

we tore up our floor and replaced all the pipes we had our tank checked its working fine not much in it but as soon as it got cold it started to smell do you have any ideas what we could do - Cheri 1/14/12

Reply:

oh why do people type in all caps.

A septic tank under a garage floor sounds like a bad idea to start with - but in any case if it smells the system may be backing up; check for drainfield flooding;

Watch out: accumulated sewer gases indoors (in your garage) can cause an explosion or can be an asphyxiation hazard - i.e. fatal

Question: septic works but smells when it's cold and damp outside

I have a septic system that works fine, however I have an unpleasant odor. ..

usually when its cold and/or damp outside. I originally had a single wide mobile home then moved it out and put in a double wide....that's when the problems started. I've tried everything with no luck. I've tried suggestions from plumbers, had plumbers out and no one can narrow down what the problem is.

When the double wide was installed the plumber put in a clean out trap....

could that be part of the problem? I had the tank pumped in the summer and it seemed to help....

but not get rid of the problem. I'm now trying to sell my house, but can't sell until this issue is resolved. Please can you offer any suggestions for me.?
Oh...in the tub and at bathroom and kitchen sinks there are those stink pipes (?) with vented tops ...

I've put new ones on all sinks. It helped a bit but didn't solve the problem. The shower in the master bath (the drain holds water) seems to harbor a bad bad odor. I'm at my wits end. - Linda 2/8/12

Reply:

When you changed your mobile home, is it possible that someone drove across and crushed a septic drain line or damaged the drainfield?

 

Question: odors from mobile home worse when furnace is running

My furnace in my mobile home sits in front of a lot of my plumbing in the bathroom. i believe because as the weather gets colder, we use the furnace, and then that's when it smells the worst

i have also noticed that while the furnace is running and then run water in the kitchen, its the worst! - Anon 10/31/12

Reply:

Look for a blocked or missing plumbing vent that is causing drain gases to back up out of a drain near the furnace return air intake

 

Question: sewer gases picked up by furnace during cool weather

Now that the weather has turned cooler and the furnace is on, we are experience sewer smells thru the heating floor vents on the upper levels of the house.

We also have smelled the same odor from the drain in the basement bathtub. There was no odor throughout the summer or spring months. Can't figure it out so far. - Deborah 11/17/12

Reply: check for sewer gas draw into cold air returns; try using a sniffer person or a TIF8800 combustible gas detector

Deborah, if sewer gas odors come out of heating supply registers I suspect that sewer gas is being drawn in at a cold air return. That may help you start looking.

Reader follow-up:

Thanks Dan
We can smell the same smell in the cold air return by our front door main level but we have very few cold air returns in this house. There is none in the basement bathroom and we have never isolated a smell from the furnace room. We did get a smell in the upstairs bathroom although that seems somewhat abated after we have constantly poured vinegar and hot water and bleach down all drains for the last week.

Last winter we had $10,000 worth of drain work done to replace the old clay ones under out house.

They put in all new clean outs to meet regulations. This was done in December and we survived the winter season without any problem with sewage smells, although it was fairly mild. Prior to this work being done our daughter lived in the basement for at least 10 years without problem.

We called the drainage company who did the work back and he checked all the drains for P traps and dry/wetness.

He claimed all was fine. Could it be the old city pipes coming into our new connection that might be a problem?

Thanks for any and all help. We are in the process of getting someone to climb our roof to check the stack for some kind of animal blockage (nest) perhaps. It's driving us crazy. The contractor said to call him back if the smell still persists which we will do. - Deborah 12/5/12

Reply:

Deborah,

I just can't hazard much of a guess at this point; I think the next approach is to use someone as a "smeller" who spends some time away from the site so that their sense of smell is fresh, then comes to the home and walks the outdoor site first, starting at the edges of the property and spiraling in towards the home to see if s/he can spot the source of strongest odor.

A similar approach can be taken using a TIF8800 combustible gas detector provided that you initialize it well away from the suspected odor source or property.

See TIF 8800 GAS DETECTOR for details about this instrument. Many home inspectors have them as do some plumbing inspectors;

I also agree with the use of checking for vent blockage or vent piping leaks; typically if the plumbing vent were actually blocked your drains would gurgle when draining.

Question: steps in tracking down & curing sewer gas odors occurring only in cold weather

I am pretty much at my wits end with the sewer gas smell that enters the mail level of my home when the temp outside goes below 30 degrees. It is very upsetting because the smell is not pleasant and is most pungent near the kitchen window. The smell continues along that same wall into our living room and family room.

My husband already went up on the roof to pour a gallon of bleach and then several gallons of water down the vent pipe. Nothing changed. Also, we had a plumbing service come out and no resolution there either. Help please. - S.N. 12/6/2013

Reply: Steps in diagnosing cold weather sewer odors

Please first check out the article SEWER GAS ODORS in COLD / WET WEATHER

let me know what questions remain and what has been done or checked so far and we'll pursue specific details for your home.

Reader follow-up:

I did read your article through before sending you my question. The only addition is that we had another plumber out again yesterday and he was very perplexed by our situation.

He suggested that we first put a turbine exhaust fan over our roof plumbing stack. He thinks that will help pull the air through.

If that does not work, he wants us to apply heated tape to the pipe in the attic leading to the roof plumbing stack. If we do that, we will need to add in an electrical outlet in the attic to plug in the heated tape. Honestly, we are not too sure what to do. Your advice would be greatly appreciated. - S.N.

Reply: cold weather odor from drains: diagnostic & Temp-Fix suggestions

The added detail in your note lets me comment further with some diagnostic suggestions: While we might on occasion apply a band-aid to a problem as a temporary fix, generally it is better to find the cause of the plumbing problem instead

. If the house is old and the odor problem is new, then the best approach is to determine what has changed or broken or come disconnected or blocked so as to cause the odor.

Adding a fix atop an existing problem without understanding the problem cause risks wasting time and money and risks failing to attend something important but not immediately obvious. Put another way, we can spin our wheels applying one band-aid after another without any success because we never took time to figure out what's wrong. Therefore

• Turbine vent band-aid repair for clogged plumbing vents:
  
  I would not add a turbine vent (which only works if wind is blowing, and should not be necessary if the vent system is unblocked, not leaking, and properly installed and designed). And when no wind is blowing, depending on its design I'm not sure that a turbine doesn't actually obstruct airflow.
  
  One would have to figure that if homes needed turbine vents to work properly we'd see them on millions of buildings where we don't. BUT at some sites downdrafts, roof shapes, terrain shapes, nearby trees or buildings can cause downdrafts in chimneys and possibly plumbing vents.
  
  In those rare cases I see experts install a wind-aimed vent cap that simply turns its closed back to the face of wind so that the vent can work.
• Bleach band-aid for clogged plumbing vents or drains:
  
  the bleach idea is that we are killing something obnoxious growing in the vent piping.
  
  But vent piping is intended to safely vent sewer gases above the building; during a bout of extra smelly sewer gases (someone flushes diarrhea down the toilet) the vent system is still designed to handle that surge in odor; bleach is not necessary and even if it completely sanitized all of the vent and drain piping (completely unrealistic) it would not prevent a problem recurrence.
• Heat tape band-aid for frost clogged plumbing vents:
  
  the theory is that frost is accumulating and blocking the plumbing vent, causing gases to then back up (more on this later) into the building. It's a good idea to determine if indeed frost is blocking the plumbing vent.
  
  If that is the case a more important problem is that drains will stop functioning properly. If that is occurring you will notice that drains served by the blocked vent become slower and may make a gurgle or blub blub sound when draining. (A partly blocked drain due to a downstream clog in the drain line will cause the same effect).

If a vent is becoming frost-blocked, the best repair is to remove the small-diameter vent and replace it with a larger diameter vent pipe. The location where this problem is most likely to occur is in a smaller-diameter plumbing vent, typically one that serves only sink drains such as a vent that only serves a kitchen.

If a vent is blocked for any reason (frost, or a frog as is in one of my photos), the result is not just slow drains and drain noises. If the vent is blocked some plumbing drains may siphon water out of the drain trap at the fixture (typically sinks or tubs). The result is sewer gas (smelly and explosive) entering the building at the drain trap.

This siphoning is more likely if a building fixture drain is served by an "S" trap rather than a modern "P" trap. Check your kitchen sink and let me know what type of trap you see.

(PLUMBING TRAPS & INTERCEPTORS)

On many buildings, especially older homes, there are multiple vent pipes that protrude through the roof, serving different building areas; those serving full bathrooms are usually larger.

At PLUMBING VENT CODES, DEFINITIONS, TYPES we give tables of vent size requirements. Take a look and let me know how that compares with your home.

IF an on-roof inspection confirms that a vent is frost clogged then a temporary fix is to add a heating tape - you can run a heavy duty extension cord to avoid adding permanent wiring if you like, waiting for better weather to correct the problem properly with a larger diameter vent.

As we don't enjoy climbing ladders and peering into vents in winter - it can be dangerous if we slip and fall, while that's the most reliable diagnostic, how else might we guess that frost is blocking a plumbing vent?

Long hot showers or dishwashers or running hot water down a drain can send lots of moisture up into the vent system; if we notice that drains are slow and noisy or odors are worse an hour or so after such fixture use during freezing weather, that's suggestive of frost clogging.

We could also try warming a heating vent from inside the attic, using a simple hair dryer - though quite a bit of warming might be needed to thaw the vent portion that extends outside above the roof.

Borrowing from our general approach to tracking down odors to their source here are some additional diagnostic suggestions:

Keep an odor log, noting when and where odors are worst (you already cite the kitchen area). Relating odors suspected to be due to plumbing vent frost-clogging to outdoor temperatures, wind, and fixture use could be diagnostic.

Note carefully where odors are worst: outdoors vs. inside (on occasion area wind patterns send plumbing vent gases down from a properly-working rooftop vent to lower building windows) and inside by room, fixture, and fixture use.

Often plumbing or sewer gas odors are ultimately traced to a loose toilet, a clogged drain, or an improper plumbing trap.

But if we are sure that at your home the odor problem is new, and only a cold-weather problem, I suspect that the problem will be traced to something that has changed, such as a drain that is partly blocked, a vent that is partly blocked, a vent that has come disconnected somewhere in the building (it was never properly glued or soldered, or it was punctured or damaged) or similar damage to a building drain.

Keep me posted and we'll take it from your next report.

Reader follow-up:

My husband just left Home Depot and got the heat tape, but will hold off after reading your response below. 

We have 2 toilets upstairs that keep running.  One flushes on its own during the night and the other takes forever to complete a flush.  Should my husband replace both toilets or should he just repair them?  We need to address this soon because the weather just dipped again to 16 degrees and the smell which was gone for 2 days is back in full force again.

Reply:

Here's where I'd start:

1. if you can't quickly fix a running toilet (you may need to replace a flapper valve or the fill valve) then turn off the water supply to the toilets that are running.

IF there is no toilet shut-off valve, most likely you need a plumber to add one - at which case you'd also at the same time replace any parts needed to stop the running toilet problem in the first place.

2. If the drain is not totally blocked you can often remove the partial ice blockage it by running very hot water down the drain for a time.

Reader follow-up:

Matt did a bunch of plumbing work on a bathtub & 2 toilets upstairs.  He is off tomorrow from work and will be continuing his repair efforts.  Once Matt has completed everything, I will let you know if the odor dissipates during cold weather.  Thanks again Daniel for your awesome guidance and feedback.

I have no news to report yet.  We have had 30 to 40 degree weather for several days, so the odor has not been present in the house. 

The weather is going to dip below 20 degrees again though.  I can then see how things go with the cold weather odors.  I am hoping all the plumbing repairs Matt did on the 2 toilets and bathtub upstairs make a beneficial difference. 

If not, Matt is going to wrap the pipe in the attic in electrical wire (heat tape).  As soon as I have feedback, I promise to let you know. - M & S N 12/23/2013

Question: storm drain & sewage ejector pump sharing effluent & sewage odors?

9/11/15 Michael Mattingly said:

Lived in home 14 years (rural) with septic field. The septic ejector pump and storm drainage sump pump are located next to each other in downstairs bedroom.

For years we have had sewage (intermittent trickle) coming from the storm drainage inlet line and dumping into the sump pump.

Obviously, the smell is not good. We have had many plumbers come out. Septic field fine, septic tank fine, pipes no leaks, snaked storm drainage line--- when water is turned on from many in home sources--- they saw water coming in slowly.

They hit an elbow connection and couldn't see beyond that. I tried a dye test. Added dye to every toilet. Have noticed blue dye in storm drain sump pump.

Assume coming from ejector pump leak? The ejector pump sewage collection is somehow communicating with the storm drainage system? Does this sound right? How can it occur? What do we do next? Thanks!!!

Reply:

Michael

I am unclear on why you are citing sewage in the storm drainage sump pump. Can you clarify where the sewage effluent is appearing: the storm drain system or the sewage ejector pump?

If the former: the suggestion is that your septic system is in failure or sewer piping leaks and is e3ntering groundwater near the house.

If the latter the problem may be a flooded septic system during storms or a failed check valve at the ejector pump.

Question: sorting out sewage ejector pump, storm drain pump, & a blocked septic system

(Sept 10, 2014) Michael Mattingly said:

Lived in home 14 years (rural) with septic field. The septic ejector pump and storm drainage sump pump are located next to each other in downstairs bedroom. For years we have had sewage (intermittent trickle) coming from the storm drainage inlet line and dumping into the sump pump.

Obviously, the smell is not good. We have had many plumbers come out. Septic field fine, septic tank fine, pipes no leaks, snaked storm drainage line--- when water is turned on from many in home sources--- they saw water coming in slowly. They hit an elbow connection and couldn't see beyond that. I tried a dye test. Added dye to every toilet.

Have noticed blue dye in storm drain sump pump. Assume coming from ejector pump leak? The ejector pump sewage collection is somehow communicating with the storm drainage system? Does this sound right? How can it occur? What do we do next? Thanks!

Reply:

Michael

I am unclear on why you are citing sewage in the storm drainage sump pump. Can you clarify where the sewage effluent is appearing: the storm drain system or the sewage ejector pump?

If the former: the suggestion is that your septic system is in failure or sewer piping leaks and is entering groundwater near the house.

If the latter the problem may be a flooded septic system during storms or a failed check valve at the ejector pump.

If someone put a tracer dye into a building drain (like a toilet) and you are seeing that dyed water in the storm drain then it sounds as if the plumbing system is not connected properly and that it may violate your local building codes too.

Question: septic odor when the bath fans run

(Sept 30, 2014) JBrooker said:
When we turn our kitchen or bathroom exhaust fans on for an extended period of time we get a septic odor.

The odor seems to emanate from somewhere around our upstairs guest bathroom. When the kitchen fan is on, the smell comes out of one of the kitchen pot lights which is right below the bathroom (but is also mild in the bathroom).

When either bathroom fan is on the smell is present in the guest bathroom. The odor does not appear to be coming from any of the drains in that bathroom (or any other drain) and the traps have all been kept wet.

If anything, the smell also seemed a bit stronger under the sink where the pipe comes through the wall (which is directly above the pot light).

That being said, the smell was also noticeable when standing in that bathroom, which lead me to believe that it was coming from somewhere higher up than under the sink (but I couldn't pinpoint where)... The plumbing vent comes out of the house on the opposite side of this bathroom and is proper diameter.

And there is no glub glub or gurgle sound from the drains ever. The pipe on the roof did not appear to be covered in snow or impeded in any way last winter when the smell was strongest. The house is very tight and does have a mechanical ventilation system in addition to the exhaust fans.

It is not present at all when the exhaust fans are off. Is this odor caused by a leak in the pipe or back-drafting, or both? -- I also posted these comments in the article for back-drafting, but saw this one was more recent. Thanks

Reply:

JB please see BACKDRAFTING & SEWER/SEPTIC ODORS

Question: sewage spilled in the crawl space

(Oct 11, 2014) LauraD. said:
3 years ago our home reeked of sewage. Upon peering in our crawl space under the house, we found it to be half full of raw sewage and had to call a company out who handles such things.

Well every year since then, when the weather starts to change from warm to cold the stench of sewage reappears, but only in the bathroom.

Lately it seems to be getting worse. My brother, who owns the house, and lives here, isn't concerned.

Whereas, I have major health issues and cannot afford to stay in the house but also cannot afford to go elsewhere. If I hadn't been all over him about it 3 years ago, he would have lived in the stench until he got sick or something else happened.

Can you give me any ideas as to why this is happening, what we can do. I've read different things it could be and relayed this info to my brother and the plumber that he is NOT, tells me whatever I tell him is not the problem...and he hasn't even bothered to check anything out! I need some advice

Reply:

Certainly you are describing an unhealthy and perhaps dangerous situation since both sewage hazards and possibly explosive sewer gas hazards could be present in the home.

See SEWAGE BACKUP, WHAT TO DO

Question: sewer gases occurring only in cold weather

(Nov 21, 2014) Marti said:
The article about the sewer gas in cold weather sounds like my situation. We have never had the pressure test or smoke test but I am thinking about it.

We have all the other things done that you can think of.
I wanted to know if they ever found out where the problem was. We deal with this every winter and it really is starting to make me sick.

(Dec 23, 2014) Anonymous said:
Every winter when you start having to turn the heat on, we have a sewer smell. No particular area can be pin pointed. We have a basement, main floor, and upstairs.

The sewer smell seems to be in the main floor of the house but with an open floor plan, it is in every area. I cannot find the cause and it is driving me mad. I cannot invite company over because of the odor. Why only in winter?

Reply:

Anon

If you are talking about forced warm air heat - a furnace heating system - your air handler could be picking up sewer gas at an air return. Look there.

...

Continue reading at SEWER GAS ODORS in COLD / WET WEATHER or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see SEWER GAS ODOR COLD / WET WEATHER FAQs-2 - more Q&A on this topic

Or see these

Recommended Articles

• SEWAGE PUMP ODORS
  
• SEWER GAS ODORS - home
• SEWER GAS ODORS in COLD / WET WEATHER
• SEWER GAS ODOR REMEDIES
• SEWER / SEPTIC PIPE CAMERAS
• SITE WEATHER or NEIGHBOR'S SEWER ODORS
• TRACK SEPTIC ODORS to SOURCE
• TRACK SEWER ODOR by WEATHER
• WET WEATHER SEWER ODORS

Suggested citation for this web page

SEWER GAS ODOR COLD / WET WEATHER FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to DRAIN SEPTIC SEWER PIPES

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Citations & References

In addition to any citations in the article above, a full list is available on request.

---

ADVERTISEMENT

---