We get the same thing...it's odd, and I don't have an answer.

We've been here 2 1/2 years and had roots taken out of the line twice, although even the plumber said he has no idea where the roots are from since there are no big trees close to it and the lines are 10ft below ground at the point where they are getting in. What we've found out is that once the roots were removed, the smell went away outside. If we smell it again, months later, we put some root killer down the toilet (not real "green" I know, but it works) and the smell goes away. Is your smell all the time? We only notice ours right after we get showers in the morning. The only times we've smelled it inside was when the floor drain dried out...we have a radon fan installed in the basement to push excess humidity out and that will suck up the gas if the trap is dry.

Thanks for the responses and explanation. I didn't have my notification set.

The smell downstairs is gone. I've been pouring water in the shower. The smell was coming from the washer drain pipe, so I'm not sure why pouring water in the shower helped, but it did. They are close together, maybe share the same line? I don't know.

As for outside, it comes and goes. I don't smell it by the drain field. It's behind the house near where the inside smell was. It's hard to pinpoint because it comes and goes in wafts--I'm guessing from the wind. I notice it the most when it's really cold. If there is a leak I guess I'll know for sure in the spring when everything melts. Will have a plumber check things out then.

Thanks for the input!

Hope you got this sorted, but thought I'd post some info if others have these issues.

As apg4 said, if a vacuum is created in your soil pipes it will suck the water out of the traps in your sinks, you will really know about it if this happens as it will stink! Check soil pipe vent for blockages. You can also fit durgo valves which open when a toilet flushes or a bath drains to prevent a vacuum being created but then seal all other times to stop sewer gasses escaping, there are outdoor and indoor types, particularly useful if your sewers really honk.

To answer the question about smells during cold weather, you need to think about the fact air of different temperatures move differently and having heating/fires on can cause backdrafting. Hot air rises, if your house is older and not well insulated, the escaping heat has to be replaced by new air, so your house is sucking air in from wherever it can (door/window cracks, underfloor voids, bathroom fans etc). If any of these places are near a soil vent or badly sealed pipe you'll get sewer smell in your house during cold weather that doesn't enter when warm.

This is further enhanced by the fact you have boilers, fires and other things running that use up air in your house, this all has to be replaced, the backdrafting suction increases.

2 other factors to consider in cold weather that add to this. All the houses in your road are connected to the drains, in cold weather they all have heating on warming the connected ends of the drains and therefore drawing sewer gas back towards houses. Lastly, if all waste water from your house goes into the same sewer (and your neighbours) then lots of warm water from baths, showers and cooking is entering. When it is very cold the sewer gas can be warmer than the outside air temp and as the sewer slopes away from your house, the warm sewer gas will rise and find its way closer to your house. Manhole covers are generally not air tight and you'll get smells by them which are stronger in cold weather due to the things I've mentioned. Any cracks/damaged pipes will also act as a vent point which will be a lot stronger in cold weather due to the above.

Solution can be multiple things, try to pinpoint the smell as best you can, clean manhole covers so they sit better, check vents are not blocked, consider if you need a durgo valve, get someone to inspect the underground drains with a camera, chrck traps under sinks are not leaking.

Good luck

HELP ME SOMEONE PLEASE .. I really am going crazy here trying to find out whats causing this odor. Its not a sewage smell its more of a pungent sweet smell. We live in a split level house and the smell is upstairs in the back bedroom. We are hooked municipal, the smell is coming from 1 bedroom with a very small bathroom with 1 sink and a toilet. We did the recipe with the baking soda, vinegar, bleach and mineral oil in that sink but that didnt do anything for the smell. For the last 3 years as soon as it starts to get cold this smell comes back. Usually if we keep the door closed it doesnt bother us as much, but this year its really bad. Even with the door closed it just reaks through down the hall all the way downstairs. We have three bathrooms and its the only one that smells like this. My husband says that there is no vent on the roof for this bathroom but the vent goes to the garage. It doesnt smell like sewage but its a horrid smell thats hard to describe and I just cant take it any longer. It cant be a dead rodent, it smells only in the winter time and by three years it wouldnt be a problem I would think. The toilet is not leaking so the wax seal of the toilet should be fine. Please someone give me some suggestions of what we could be doing.

make sure the sink was at least installed with a p trap and change the toilet seal. Usually wax is used. unless you get gurgling in toilet or sink the vent isn’t causing issue wouldn’t think as sewer gas would Come from the gurgle bubbles. Next would be downdrafts in winter months causing the gas to be stronger (held down in vent by pressure) and forced out via bad wax seal or pipe holes

I don't see how any toilet - save one on a boat or R/V - could possibly function without a vent stack. "but the vent goes to the garage" would not be approved by any building inspector anywhere in this country. Perhaps it was a "SPOT" - stupid previous owner trick.

There is one possibility - other than installing a toilet and vent properly - which apparently was not done. The vent or soil pipe could have been pierced by a drill, nail or screw, especially if PVC was used. As an appraiser. I've seen that happen before.

And yes, I *almost* made that rookie mistake myself, installing a new cabinet over the toilet. Since this is a 1938 house with plaster on lath walls, I was using a stud finder and drilling pilot holes. One was in an unexpected location, but it was *perfectly* placed. But it wouldn't drill...and that's when I realized it was the cast iron vent stack. No harm done....

Thank you Troy all that was done. It has warmed up again, so for now there is no more smell. I know when it gets colder though it will return. I read somewhere else that it could be from the manhole on the street that when the heater comes on for the pipes the gas is pushed towards the houses. I don't know if that could be true but it sure sounds possible. I just wish we could find a solution to this strange phenomenon.

You have *heated* sewer pipes? Where do you live? Fairbanks? But no, that is simply NOT possible with a properly installed and functioning vent system. Vent stacks serve two purposes: first, to 'break the vacuum' when a slug of water gets flushed. Otherwise, any residual water in the toilet bowl would get sucked downhill. And with a 'dry' bowl, sewer gas would enter the home. Secondly, any sewer gas that does find its way inside gets vented straight out through the roof. Conceivably, a properly-installed vent stack could be blocked by a bird's nest or other debris.

We are having the same issue! we live in a trilevel and the smell starts around November and throughout winter In the upstairs master bed/bath. the smell come and goes. Mu husband usually doesn’t smell it but I worry about it affecting our health. We live in a subd where we have our own septic and well if that helps. the septic was emptied in the spring, so that isn’t the issue. Any advice?

Hey, original poster here. 7 years ago since I posted this and the smell still comes and goes in the winter. Despite the informative replies, I've never been able to fully wrap my head around the mechanics of it. Seems like it could be a number of things.

So a few weeks ago I got a new roof and I mentioned this smell problem to the roofer. He extended the "stink pipe" (same thing as a vent stack?) about a foot and put a curved end on it so it points downward. He said that would keep the cold air from getting trapped, as well as keep snow from settling over the opening. I'm unclear how a curved end facing downward will untrap cold air. Wondering what your thoughts are on this.

Anyway, we'll see what happens when we get some snow. I already smelled the smell when the temperature dropped, but it didn't last long.

If it isn't a SPOT - stupid previous owner trick - of drilling into the vent pipe, it might be a function of the heating system, but only if that is oil or gas fired. 'Modern' houses are well sealed and super insulated; without additional make-up air from outside, the furnace will create a slight negative pressure as flue gasses exit out the stack. And this is only an issue in winter...when the furnace is used. Exhaust fans in kitchen and baths exacerbate this. This negative pressure 'imports' sewer gasses. Try cracking open a window closest to the furnace.

apg4

Any suggestion if the furnace is in the basement?

Also, how can you tell if a previous owner drilled a whole in it without tearing open the walls?

Well, if someone pierced a vent stack, the smell will be highly-localized. (PVC piping didn't come into usage in the US 'til the mid'50s; earlier stuff was cast iron, requiring significant effort to damage.)

Most every basement has a window, though maybe not operable. I think that windows in basements might be part of the NBC these days. Some local codes require *operable* windows that can double as an emergency exit.

I am having a similar issue in my apartment. It is 2 story with only a closet directly in front wheh you walk in and the stairs immediately left and the rest of the unit is upstairs. The smell is only right when i walk in and about halfway up the stairs. It is not in the closet and it happened last year around this same time, went away and is now back. Could this be the pvc stack up? I plan on calling maintenance about the issue.

I have a similar problem EXCEPT, when I shower in the morning I smell a slightly sweet/sewer smell in the house. I believe most is coming from basement but can't locate. THIS SEEMS TO ONLY HAPPEN IN WEATHER CHANGES FROM HOT TO COLD AND COLD TO HOT seasons. Lasts a month then goes away for the most part. I have tried to make sure there is water in all drains (Toilet, shower, sink, washing machine drain) but that doesn't seem to help. Been going on like this for years. Any ideas? Thanks so much