Sewage odor from plumbing

[Angelfire]

Hiya,
I have a cabin in the mountains that I need some help on. Anytime we run the sink or shower for any length of time, we get strong sewage odors outside most noticeable near the side of the cabin where the roof vents are located. I know nothing about plumbing design per se, but can fix it when needed. I’m on a septic system that was recently pumped and was diagnosed as being healthy. I have the sink, tub, toilet that all drain to a main line where there is a p-trap. From there it runs to the septic. I have not looked to see where the vents are tied in. Short of trying to place carbon filters on the vent lines, are there any recommendations of where to start my search for the issue?
Cheers

 

[spudley]

I'd add extensions to the vent pipes. You're probably getting a downdraft.

 

[Jackfre]

The closer the vent arms are to the individual fixtures the better the system will operate. You say the odors are strongest by the vent terminations. Perhaps you are getting a downdraft off the roof to carry those distinct odors back down to you. Either extend the vents or relocate them further up the roof line

 

[Morgan44]

Is there also a clean out at ground level near the p trap you speak of? Unless the roof is unusually short, vents through the roof usually don’t cause an issue.

 

[Angelfire]

Is there also a clean out at ground level near the p trap you speak of? Unless the roof is unusually short, vents through the roof usually don’t cause an issue.

The clean outs are located on the other side of the house nearer to the septic

 

[Angelfire]

The closer the vent arms are to the individual fixtures the better the system will operate. You say the odors are strongest by the vent terminations. Perhaps you are getting a downdraft off the roof to carry those distinct odors back down to you. Either extend the vents or relocate them further up the roof line

I may try that. Seems it doesn’t matter if there is a breeze or perfectly calm outside. The cabin has a gambrel style roof and the vents are located on the upper slope.

 

[spudley]

The main entry door on my house is on the east side. We, like most of the non coastal US, have predominant wind patterns from the west. Vents are on the east side of the gable roof. You guessed it.

 

[ransil]

The roof vents on my house have extensions 3-4ft high, PO said he was getting odors , he said that fixed it and i have never noticed it. Cheap fix worth a shot, coupler and some pipe.

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[Doc995]

Could possibly be that the actual vents are clogged? This happened to a neighbor of mine some time ago...can't remember what was clogging it but it WASN'T an animal, lol.

 

[Northislander]

The roof vents on my house have extensions 3-4ft high, PO said he was getting odors , he said that fixed it and i have never noticed it. Cheap fix worth a shot, coupler and some pipe.

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Just a heads up if you try this fix with lead roof flashings you have to seal the pipe to the lead. Not a problem if you have rubber boot flashings or neoprene flashings

 

[Captain Spaulding]

You should have a P-trap at the shower and sink, not a single trap for multiple sources. Your vents should be blocked from the septic tank by the water standing in the traps. My bet is you have something odd with the trap or too much fall to the tank causing the trap to be emptied after water use.

 

[bad_idea]

What changed? Folks are suggesting fixes that fix a design issue or install issue. If you didn't previously have a problem, but do now, then I find it difficult to believe it is an issue with the initial design and install. I'm no plumber so I have zero idea what your issue could be. I would start with Doc995's suggestion as that is a possible change in conditions.

 

[redneckcharlie]

The op may be incorrect on some type of ptrap on the main line. If it is indeed present then his home was not inspected by a building inspector during construction nor was it approved by environmental health that does the septic inspections here. That being said, a vent location is not dependent on the location of a shower trap if a shower is present. The vent location and sizing is dependent on the number of fixtures it services at the particular location. 1 1/2” for two fixtures(toilet and sink), or a 2” for a 3-4 fixture setup(full bath). It is very common here to get sewer gas from septic installs where the roof venting is short. On applications where there is an evaporative cooler present on a roof, the venting needs to be above that application, as it does the furnace venting. I doubt he has that scenario in Angel Fire due to the low summer temps and elevation.

You should have a P-trap at the shower and sink, not a single trap for multiple sources. Your vents should be blocked from the septic tank by the water standing in the traps. My bet is you have something odd with the trap or too much fall to the tank causing the trap to be emptied after water use.

 

[Angelfire]

You should have a P-trap at the shower and sink, not a single trap for multiple sources. Your vents should be blocked from the septic tank by the water standing in the traps. My bet is you have something odd with the trap or too much fall to the tank causing the trap to be emptied after water use.

I definitely have traps on the sinks, that much I can be sure of. I'll need to climb down into the crawl space next time I'm there to verify the tub/toilet. Thanks.

 

[Angelfire]

What changed? Folks are suggesting fixes that fix a design issue or install issue. If you didn't previously have a problem, but do now, then I find it difficult to believe it is an issue with the initial design and install. I'm no plumber so I have zero idea what your issue could be. I would start with Doc995's suggestion as that is a possible change in conditions.

Nothing's changed. It's been this way since I've owned the cabin....

 

[nh_yota]

Where is the vent for the septic tank?

 

[Angelfire]

The op may be incorrect on some type of ptrap on the main line. If it is indeed present then his home was not inspected by a building inspector during construction nor was it approved by environmental health that does the septic inspections here. That being said, a vent location is not dependent on the location of a shower trap if a shower is present. The vent location and sizing is dependent on the number of fixtures it services at the particular location. 1 1/2” for two fixtures(toilet and sink), or a 2” for a 3-4 fixture setup(full bath). It is very common here to get sewer gas from septic installs where the roof venting is short. On applications where there is an evaporative cooler present on a roof, the venting needs to be above that application, as it does the furnace venting. I doubt he has that scenario in Angel Fire due to the low summer temps and elevation.

Thank you. I will climb under the house next time I'm there to verify what I have (was going off memory with this post). I definitely have individual traps for the sinks but need to verify for the shower/tub (one unit) and toilet. I'll also look to confirm just what size vent I have up there. I can say for sure that it's quite short above the roofline where it penetrates so that may very well be the issue. And you are correct, no AC at the cabin. No need for it.
Cheers.

 

[pattenp]

Maybe your tank is full. Have you had heavy rains that could cause the drain field to overfill? I had a neighbor who's tank was filled and overloaded the drain field and I could go outside and it smelled like a sewage treatment plant.

 

[59 wagon man]

I have had buildings where cleanouts were installed on the opposite end from where the sewer exits to make snaking the main run easier maybe a plug is loose.

 

[spudley]

Hiya,
I have a cabin in the mountains that I need some help on. Anytime we run the sink or shower for any length of time, we get strong sewage odors outside most noticeable near the side of the cabin where the roof vents are located.

I think you should donate time at this cabin to all GJ members to come and investigate this problem. If you keep the fridge stocked with beer, I'm sure we could fix it in a few short years....

 

[JRC3]

One thing for sure, do not pour bleach or any cleaners down the drain to help with the problem.

In fact, now that I think of it, were any chemicals or bleach washed down the drain? Even a little, like you normally have used before? The recent pumping obviously lowered the bacteria numbers and might make a healthy septic tank vulnerable to low amounts of bleach or cleaners that normally did not cause a problem.


Also, has the tank completely filled back up since the pumping? Depending on the baffles inside a half empty tank may have more surface area exposed to the vent pipe. With that said, concrete baffles also deteriorate and break or crumble way. It's actual very common.

 

[Angelfire]

Maybe your tank is full. Have you had heavy rains that could cause the drain field to overfill? I had a neighbor who's tank was filled and overloaded the drain field and I could go outside and it smelled like a sewage treatment plant.

This odor has been present for a long time even after having it pumped (regular maintenance) and isn’t really affected by the seasons. Currently there’s a foot of snow on the ground but I get it regularly in the summer too. Usually dissipates quickly though once water is not flowing in the house. It takes either someone taking a shower or a long dishwashing session at the sink for the odors to appear
Cheers


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[Angelfire]

I have had buildings where cleanouts were installed on the opposite end from where the sewer exits to make snaking the main run easier maybe a plug is loose.

I need to look at the clean outs to make sure of this. If a cap is loose or damaged, could it cause odors to escape from the vents on the roof?


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[Angelfire]

I think you should donate time at this cabin to all GJ members to come and investigate this problem. If you keep the fridge stocked with beer, I'm sure we could fix it in a few short years....

Oh my we’d have some fun for sure particularly with the sleeping arrangements as it is very small!


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[LOW1]

A toilet will have a built in trap so you shouldn't find a separate one for that. And if you didn't have a trap under the shower I think that you would have an indoor odor problem.

I don't know what to think about a "master trap" serving the entire drain system. That would be a bit weird.

But you don't have any drainage problems right? Toilets flush, sinks drain, etc.? If there was a trap problem or a full septic tank I would expect that there would be drainage problems and/or indoor odor problems.

I'd extend the roof vents before I went any further. Are they abs plastic (black) or pvc plastic (white)? If so I would try adding a 2 or 3 foot long extension of the same material to each with a fitting. I wouldn't glue anything together until I found out that was the solution. Wait a few weeks and see if it improves the problem. And maybe you only need to do one of the vents to fix the problem, if you have more than one.

 

[Angelfire]

A toilet will have a built in trap so you shouldn't find a separate one for that. And if you didn't have a trap under the shower I think that you would have an indoor odor problem.

I don't know what to think about a "master trap" serving the entire drain system. That would be a bit weird.

But you don't have any drainage problems right? Toilets flush, sinks drain, etc.? If there was a trap problem or a full septic tank I would expect that there would be drainage problems and/or indoor odor problems.

I'd extend the roof vents before I went any further. Are they abs plastic (black) or pvc plastic (white)? If so I would try adding a 2 or 3 foot long extension of the same material to each with a fitting. I wouldn't glue anything together until I found out that was the solution. Wait a few weeks and see if it improves the problem.

Regarding the "master" trap idea, I'm going from memory from the last time I was under the house.....wasn't specifically looking at the plumbing so when I'm up next, I'll be sure to verify that's what's there (or more than likely, not). The vents are black ABS. No drainage issues with any of the drains.....no back ups!
Cheers.

 

[Angelfire]

One thing for sure, do not pour bleach or any cleaners down the drain to help with the problem.

In fact, now that I think of it, were any chemicals or bleach washed down the drain? Even a little, like you normally have used before? The recent pumping obviously lowered the bacteria numbers and might make a healthy septic tank vulnerable to low amounts of bleach or cleaners that normally did not cause a problem.


Also, has the tank completely filled back up since the pumping? Depending on the baffles inside a half empty tank may have more surface area exposed to the vent pipe. With that said, concrete baffles also deteriorate and break or crumble way. It's actual very common.

The only things that go down the drain are dish soap from the kitchen sink, toothpaste at the bathroom sink, soap/shampoo at the shower. We don't have a dishwasher.

I can't see if the tank is full or not. I'd have to dig down to it and well, the ground is frozen solid at the moment.
Cheers.

 

[59 wagon man]

you do have vents thru the roof and not studor or provents

 

[Toomanytools?]

Nothing's changed. It's been this way since I've owned the cabin....

So new cabin, old cabin you have owned it for ? Just started or always was a problem since you owned it? Getting at the fact if it's been like that for 20 years could be a design issue, if just started last year could be a clogged vent.
It's pretty basic in design, could be the vents are blocked by a big tree and the gases sit for a bit before being carried off. Maybe some ideas here.

http://www.balkanplumbing.com/outside-sewer-smell-in-house-causes-cures/

 

[Angelfire]

So new cabin, old cabin you have owned it for ? Just started or always was a problem since you owned it? Getting at the fact if it's been like that for 20 years could be a design issue, if just started last year could be a clogged vent.

It's pretty basic in design, could be the vents are blocked by a big tree and the gases sit for a bit before being carried off. Maybe some ideas here.



http://www.balkanplumbing.com/outside-sewer-smell-in-house-causes-cures/

I’ve owned for 23 years (definitely not the first owner. Was built in ‘76). Just now am I putting in some effort to rectify. There are no tree branches over the house. Thanks for the link above. I’ll read that and I think I need to look things over a bit more (ie p-trap locations, clean outs, etc before I do much with it.

Thanks all for giving me some ideas to pursue


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[was2]

Thought we were having sewage odor at weekend getaway with septic. Electric water heater anode rod went bad and the rotten egg odor could kill. Replaced anode.

 

[kbs2244]

Before you add 3 feet on the vent pipe think about a anti downdraft cap.
They are simple slip on an 2,3,4, or 5 inch pipe and add less that a foot of height.

They were most often used to prevent downdrafts from blowing out pilot lights on the pre spark plug gas stuff.
But they do a good job of breaking up the air flow across the pipe.

 

[59 wagon man]

if a plug is loose in the crawl space the odors may never make it to the roof vent

 

[ColoMid]

The home I have now had a terrible septic odor in the back yard whenever the breeze
blew a certain way. It's on city sewer and happens to be at a hill top. I suppose my
plumbing is collecting gas from the lower elevations and passing it thru and out.
Research on the net suggests vents should be as high as the roof peak. Of course they
are not in most cases. It happens that I had a length of ABS pipe to try and bought a
coupling. Slipped it all together and not a single odor since a year ago.
RichD

 

[JRC3]

These are the baffles in my older septic tank, there is one at both ends. The baffle on the inlet is there to keep the floating grease and sludge from clogging the inlet pipe. It's also there so water rushing in does not disturb the surface, which will cause excessive odors. The access lid also rests against the baffle preventing gas from entering the inlet pipe from the house and on to the vent.

It's pretty common for these cast concrete baffles to erode or break off, especially bad on the out side to the drain field. Age is of course the culprit, but acidic/low pH water shortens the life. Even if the source water isn't acidic things like A/C, dehumidifier or other gas appliance condensate that might be drained in is. A bad baffle can usually be fixed by switching to a PVC T type baffle made from ordinary fittings.

Basically your tank probably has 2 or 3 access holes and the pump guy only opened the main cover to pump it out and didn't even see the baffles.
Especially if the holes are buried and would require more digging to find and open them. Not saying this is your problem, but it's where I would look.



These pics are of mine. Notice how the one is eroded while the other looks perfect. The eroded one is on my drain field and has since had a PVC T and effluent filter installed. These are old pics before and of a lot of work I did to the tank and riser covers. The house had sat for several years. Some tanks have a 3rd access in the middle for pumping.

 

[1921runabout]

I had an odor problem spring up at my home. Never had it before, then suddenly the odor came and it seemed to be coming from my vent pipes. I checked everything out including hiring a plumber to run a camera down my plumbing pipes. I also had the city clear the main line in the alley. All checked out good, but the odor continued.

It seemed to me that I was getting some kind of siphon from the main City line from the alley. We had a new housing subdivision built up stream from us and that could have contributed to this.

I researched and found this product, ODORHOG. I bought one for ever vent pipe. Easy to install. The odor stopped as soon as installed these. Have never had a problem since. Check it out.

https://odorhog.com/