Septic Odor

Jalopy · #1 01/03/10, 11:47 AM

Well it's back. Every winter when the temperature drops and stays below 0 the septic odor begins in our guest bathroom. We built the house in '03 and beginiong in the winter of '05 whenever the temperature drops below 0 we get the septic odor. We do not use that shower regularly but we do run water to keep the trap filled. We do use the toilet and the sink regularly. The sewer vent does go up through the wall and exits the roof and it is not covered or frozen shut as there is no drainage or sound problems. I am wondering if it is a poor conedction on the vent pipe but why does it onlysmell when it is so cold and not the rest of the year? Over the Holidays it began and I used some left over perfume from my wifes stash to put down the drains and it helped but it did not last long. Now that does not work and that was the only time we ever had it work. Any one have ant suggestions that i can check out.
BTW that is the only room where the smell originates. Non of the other drains or toilets smell.

Rocky Fields · #2 01/03/10, 12:03 PM

Why don't you run the shower and see if it goes away?

Joshie · #3 01/03/10, 12:15 PM

What did they say when you had the septic company out to check it? Have you had it emptied? It's recommended that you have septic tanks emptied every two to five years.

Harry Chickpea · #4 01/03/10, 12:26 PM

I think you may be right about it being a bad vent pipe connection. Cold may be contracting the pipes and opening up a gap a little more.

Beeman · #5 01/03/10, 12:36 PM

The reason in cold as it was explained to me was your septic is like the woodstove and your vent is the chimney. Obviously it's warmer in the septic so the heat rises up the vent bringing the smell with it.
You might be on to something with the bad connection in the wall.

I had a similar smell problem but mine was coming from the A/C coil. The drain was wicking up the stink.

**highlands** · #6 01/03/10, 02:35 PM

Septic company? What is that?

But onward ho... My guess is like your guess, poor ventilation of the stack. The stack might not be properly connected. The stack might not be tall enough. It might not be high enough above the roof. Is it getting covered at the top and closed off? Is the house so tight that it is back drafting in the winter? e.g., heating system such as wood stove draft, drier draft if you have one, etc? Another possibility is wind effects. If the stack exits on a wall instead of roof it might do this, or if there were close by things causing turbulence that could come down the stack.

The reason you might not notice it in other seasons is better room ventilation during warmer months. Then as you're closed up more in the winter it becomes more noticeable.

A solution would be to create more positive in-flowing air somewhere else. We put in 70' long 4" pipes under insulation under soil - insulation since we have a short distance to ledge. We draw in fresh air through the pipes. The soil warms the air and keeps the house supplied with fresh air in the winter. Google Earth Air Pipes or Tubes here's how we did it:

http://sugarmtnfarm.com/blog/2008/09...air-tubes.html

and here is a Wiki on it:

http://en.wikipedia.org/wiki/Ground-...heat_exchanger

Cheers

-Walter
Sugar Mountain Farm
in the mountains of Vermont
http://SugarMtnFarm.com/blog/
http://HollyGraphicArt.com/
http://NoNAIS.org

Jalopy · #7 01/03/10, 02:47 PM

Thanks for the replys. Yes the house is tighter in the winter and we do have a great deal of insulation so there could be the downdraft problem. The vent stack is higher than the roof ridge and only 18-24" laterally from it so there is not snnow drifted around it and there is good air flow over it but there could be a down draft in this frigid weather. As for having the septic tank pumped that shpuldn't be necessary as it was new in "03 and it is 1250 gallon tank and there are only my wife and I as our son moved out in January of 'o6. and if that were the problem there would be odor at other showers and drains as the one in the basement is closer to the septic tank than any other. We have and do run water in the trap in the shower in the guest bath and it does not solve the problem. Thanks again for your ideas. JLP

Grandmotherbear · #8 01/04/10, 05:38 PM

RV dealers and Harriet Carter Mail Order sell a super strngth bathroom deoderizer- 1 drop in the toilet supposedly is all it takes but needs to be refreshed every flush- I have no experience with this. Usually an odor at my house means septic needs pump..

rancher1913 · #9 01/04/10, 07:09 PM

the problem is inside your vent pipe. if the pipe is in just the wrong spot for weather even if it is not blocked by snow, the moisture vapor exiting your pipe freezes and blocks the vent. the further north you go the larger vent pipe required to offset this. only sure cure is to increse your vent through the roof to the termination point. this happens to the new furnaces that exit the side of the house as well.

seagullplayer · #10 01/04/10, 08:23 PM

I know a guy that had the same smell complaint last winter at his house, turns out it had something to do with his high efficient furnace vent. As I understood it, he had to pour water down the pipe every so often in cold dry weather?

Maybe someone on here knows more about it, I have a wood stove so I am clueless…

meanwhile · #11 01/04/10, 09:03 PM

We had a mystery septic stink and after all sorts of sniffing and snuffing around - and checking every pipe in sight......we put an extra Vent Stack to the out-going line, made use it went way up over roof line and that solved the stink.

At one of our Cabins, we had a smell and discovered that altho there appeared to be a Vent Stack - it was not even hooked to anything and the previous owner had just used one of those terrible under the sink do-dads. We hooked the vent stack up and that solved it.

Good luck

ronbre · #12 01/05/10, 08:12 AM

our guest bath when it isn't used often enough will get smelly..you gotta use them..regularly ..use a little bleach in the drains..after you run some water through them enough to get the traps all full..but you might be right about the vent..also ..yes get it pumped !!!

The Paw · #13 01/05/10, 08:47 AM

It doesn't sound like the vent was properly plumbed in the first place. The only way for sewer gas to come back into the bathroom is if it can get past the trap somehow. Even if the vent is downdrafting due to cold air, the smelly gas should not be able to come into the bathroom, it should be blocked by the trap. (downdraft can definitely be a factor though. In my last house, when the wind really started to whip, you could see the air pressure cause the water in the toilet bowl to move).

I would guess that one of three things has happened.

1. The water in your traps is evaporating faster than you think.
2. Maybe you don't have a proper trap in the shower to start with
3. Maybe the vented gas is being redirected back through a bathroom exhaust fan. Sometimes people cheat and tie the fan exhaust into the vent stack to save putting another hole through the roof. That would definitely cause it.

Good luck

**Cabin Fever** · #14 01/05/10, 09:24 AM

How close it the roof stack (vent) to the bathroom's exhaust fan vent?

Joshie · #15 01/05/10, 09:53 AM

Quote:

Originally Posted by highlands

Septic company? What is that?

Look in the phone book. It is recommended that septic tanks are emptied every two to five years.

#16 01/05/10, 10:57 AM

Try replacing the wax seal under the toilet .

**Cabin Fever** · #17 01/05/10, 01:28 PM

Quote:

Originally Posted by WV Hillbilly

Try replacing the wax seal under the toilet .

IMHO, this is likely the best advice I've read regarding your problem. If the odor is in just one room of the house and that happens to be one of the bathrooms....and there is a water seal in the shower/tub, toliet and the sink traps....the only way that an odor can get into that bathroom would be thru a cracked or ineffective wax toliet ring....right?

Gianni · #18 01/07/10, 11:25 AM

Use a flashlight to see that there is water in the traps. Wind will siphon them dry. I vote for a gap in the vent inside a wall or as above an improperly sealling wax seal.

**Ross** · #19 01/07/10, 11:42 AM

I'm inclined to think its the toilet seal alright, but house depressurization could affect only one room...... the one with the bad seal. If that bathroom is the easiest route for the vent air to back draft and burp through the shower or sink drain traps (wow have you got a problem then) or through a cracked vent pipe (or that toilet seal) or if the bathroom fan is tied into the septic vent as suggested depressurization could be drawing in the septic smell.
A true high efficiency furnace uses sealed combustion so it draws in air to burn and vents out the flue gas. Mid range furnaces could have a combustion air inlet (it could be blocked with a mouse nest as I've read about here on HT) or they may need one especially if you've been working at sealing up your house. A new kitchen range hood could be moving so much air it's litterally changing the air pressure in the house, so too an out of balance air exchanger. Wood stoves are good at evacuating air from houses too. Winter septic smells are a notable symptom of house depressurization but just fixing the seal or crack or bad vent is only half the job. Once it's fixed your furnace or stove could start back drafting and thats worse!