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Septic gases

| Posted in General Discussion on January 22, 2002 01:07am

*
My house was built 3 yrs. ago and since day 1, we’ve had septic odors outside. For the first 2 yrs. we convinced ourselves it was a neighbor’s house, but it has gotten worse over time. Our septic tank is only about 8″ below ground (we know the exact location due to the rectangle of dead grass), so we thought it was from that, but recently we’d noticed it in the attic (badly). So now we think it’s the vent system. Any ideas on fixing this problem, assuming the vent system was installed properly? Does it perhaps have something to do with winds and the gases settling to the ground?

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  1. Wayne_Law | Jan 19, 2002 12:38am | #1

    *
    The most likely cause is that the vent was not installed properly. It's either venting into the attic or has come loose in the attic. Maybe one of the vent risers was never hooked and left open in the attic even if the rest of them go through the roof.

    It could also be that the vent is done properly but too close to where you spend time outdoors.

    Someone else might have additional ideas.

    1. Ed_Lewis | Jan 19, 2002 12:59am | #2

      *We had a similar problem every time we went out of doors. My wife noticed that the water in the toilets quivered when the wind was blowing hard. This led me to assume that the wind was creating a vacuum moving across the top of the vent pipes and drawing the sewer gases out.At the suggestion of a plumber, I put ABS Auto Vents on top of each of the vent pipes. This stopped the water movement, but didn't eliminate the odor. I finally got rid of it completely by sealing the lid of the septic tank with a healthy dose of expanding foam.

      1. Terry_Smiley | Jan 19, 2002 05:13am | #3

        *EdI have the same problem on occasion, never thought of sealing the tank. I'll give it a try and let you know how it works.Thanks you may have just solved an annoying problem.Terry

        1. piffin_ | Jan 19, 2002 05:38am | #4

          *A tank needs to be pumpedout every couple of years to keep solids out of the field unless it is overdesigned. Sealing it with foam glues it closed. I would just cover it with plastic and clay type soil.A taller vent stack can help it vent away too. But since the smell is in the house I suspect a leak inside. It should be venting out and not in if installed right.

          1. Luka_ | Jan 19, 2002 05:51am | #5

            *Every couple years ???!?Dang, Piffen, what do you eat ? Rocks ?

          2. Jim_A._Jensen | Jan 19, 2002 07:59am | #6

            *Hoov, Install a Running Trap, that will solve your problem.Install the running trap in your yard line. No, you can not buy them, but you can make your own, it is a soft shaped trap,same size as your yard line.As far as pumping septic tanks, I try and check mine at least once a year,4-6 inches scum on top, gray water in the middle, and 4-6 inches of sludge on the bottom, this is what I "like" to see. J.J.

          3. Ted_LaRue_ | Jan 19, 2002 08:45am | #7

            *Glue a short section of drain pipe (about 10") to an elbow, and then glue the elbow to the inlet pipe just inside the tank so that the short pipe is pointing straight down into the tank. You should be able to do this through the access hole near the inlet end of the tank. It's easiest to do this right after the tank has been pumped.The idea is to create a trap. When the tank is full, the fluid level should be above the end of the short pipe on the elbow, so gasses can't escape, even though new fluids can easily enter.This is more effective than sealing the tank. Gasses can escape even a sealed tank through turbulence. I used the elbow, and sealed the tank too. And don't get carried away sealing the access lid, or you'll be sorry the next time you try to open it. The foam Ed Lewis suggests sounds like a good idea. A guy up the road from me used a lot of silicon caulk and had a miserable time getting it open a few years later.

          4. David_Thomas | Jan 19, 2002 09:27am | #8

            *Another possibility is a dried out P-trap. If there is a sink or floor drain or laundry discharge pipe that is seldom used, then the water in the P-trap can dry out, allowing gases from the vent system (septic or just from within your house) to enter that room. Pour some water in to fix the problem. If you are not going to be using it for a long time, put in a pint of mineral oil which won't evaporate away like the water does. -David

          5. Boss_Hog | Jan 19, 2002 03:23pm | #9

            *I'm thinking kinda like Wayne, that something's wrong with the venting. Either the vent doesn't go out the roof, or one of the fixture vents wasn't carried up through the wall into the attic and joined up with the main vent line in the attic. You probably need to go up in the attic and look at your vent lines. Is there a vent line coming up into the attic over each toilet and sink location ? And do they all join together and go out through the roof?One other thought - Have you called your plumber back to look at the problem?

          6. Dave_Richeson | Jan 19, 2002 09:00pm | #10

            *If you have a basement floor drain or a clean out is better, use a smoke bomb to find the leak. With the clean out you just light the smoke bomb and lower it into the pipe with a piece of tie wire wrapped around it. The smoke should come out of the vent stack only! Any place else, you got a leak. Make sure you don't have any dry traps as mentioned above,and the weather is nice enough to open the house up incase the leak is inside. Flush a toilet as soon as you finish the smoke inspection, to but out the smoke bomb. Also be sure to keep the clean out closed durring the test. The same thing can be done with afloor drain after sucking the water out of the trap with a wet vac, and agian sealing the drain durring the test. If there is a slight breeze the day you do the smoke test, you also get to see where the stink goes, once it leaves the stack.Ted, your configuration is code here.Dave

          7. Dave_Richeson | Jan 19, 2002 11:31pm | #11

            *Almost forgot. Only smoke test your system if the septic tank inlet pipe is as Ted has it drawn or you use a 3 or 4 inch plug inserted in the pipe. This prevents any questionable gases from being exposed to a possible ignition source(smoke bomb).The whole DWV system should have been wet tested durring the inspection of the rough in plumbing. This ussually occurs before the septic tank is installed.(Has to in my area.) So, as others have pointed out, it is either the tank, or something got broken after the wet test. It might be something as simple as a drywall screw in a vent pipe and the pipe has finaly broken at that point. Natural chiminey affect would draw the gas up the chase wall and into the attic.

          8. Hoov | Jan 19, 2002 11:47pm | #12

            *Thanks for all the advice. The plumber will be taking a look and so now I know what he should be thinking about. I looked in the attic, and it raised another question, the run of a couple of the lines to the main going out the roof is about 25' horizontal. Is there a suggested or required max. run?

          9. splintergroupie_ | Jan 20, 2002 12:12am | #13

            *Hoov, there should be rise on the vent pipes just like a drain line.I've cured my septic smell woes by putting a coupling with activated charcoal on top of the vent stacks. Use a 1/4" hardware-cloth circle sitting on the ridge inside the coupling, fill it with fish tank charcoal, shove it on the stack (no need to glue) and for <$5, you may well be smell free, unless you have a bad joint in the attic as well.Or you can pay more and order one ready-made. Here's a link to Orenco's catalog page.http://www.orenco.com/catalog/PF12.asp?pf=12This may not meet local code (depends on whether they consider this as stopping of merely filtering the gasses), but it has worked for my house for a few years on a formerly unbearable problem.

          10. Boss_Hog | Jan 20, 2002 01:44am | #14

            *My plumber told me that you couldn't put any kind of cap on a vent stack, as it might frost up during cold weather and get plugged with ice. I wonder if that's code in Illinois, or just his opinion, or what ?

          11. splintergroupie_ | Jan 20, 2002 02:55am | #15

            *Boss, been through this argument with a few dozen people. We had four-inch frost crystals hanging off the barbed wire a couple weeks ago with 8* and 85% humidity (go figure) and there was NO problem with my vent stacks, though i now catch an occasional whiff when go outside after doing laundry and should change the charcoal, i suppose. Also hasn't been a problem for 3+ (i'm losing count) winters before this one. We've gotten to -31*F in that time, and -20* for ~two weeks once period. Choices are breathing and breaking code (which has not attained the status of natural law in my book, by any means), or conforming and choking on eau de poo. My patio and garden, formerly unusable spaces to me due to smell, are now a joy.

          12. piffin_ | Jan 20, 2002 03:14am | #16

            *Luka,No rocks but my daughter has a lot of girl friends and TP mysteriously disappears by the roll when they are visiting.Seriously, This state has loads of clay soils which don't perc very well and the state recommends pumping every two years. I went three and it was almost two long. Keeping the solids from getting out of the tank and into the field will help your system last almost indefinitely. Priced a new system lately?

          13. splintergroupie_ | Jan 20, 2002 03:36am | #17

            *Piffin, have you checked out the newer kinds of leach line, the 11 1/2" corrugated ABS stuff in a sock? It was recommended to me for clay soils by the sanitation dept. where i live; they said you could backfill with whatever, didn't even need gravel. I couldn't find a good link on this, sorry. Good excuse to rent a mini-excavator, yes???

          14. piffin_ | Jan 20, 2002 03:56am | #18

            *A lot of the new ones by homeowners are being done with that but it is required to lay in a sand bed here. It is an easier, cheaper way. It also fits a side hill slope better. Regardless, whether your field is that, pipes, chambers, or some other new systems; the field is for straining and sanitizinf the fluids. If you fill it with solids, it will fail. The solids need to digest in the tank which is why they settle to the bottom of it. Add too much solids from a garbage disposal, grease, TP, tampons or the dead pet bird and the tank will spill into the field.

          15. Ted_LaRue_ | Jan 20, 2002 08:29am | #19

            *This system is the type splintergroupie is referring to. ADS pipeThis system allows your field to be only 75% (possibly 50%) of what is normally required if your local authorities allow that reduction; they did here. There are clones of this brand which may be cheaper. Infiltrator

          16. splintergroupie_ | Jan 20, 2002 10:35am | #20

            *Thanks for correcting my acronyms, Ted. No wonder i was having trouble googling!

          17. Dave_Richeson | Jan 20, 2002 05:00pm | #21

            *Ted,The second link you gave us, is the system we had installed, after the artifical wetland, at my in-laws house.The problem with that system is it still reguires at least a foot of percable soil around and over it. The chambers are also susceptable to any traffic heavier than a riding lawn mower. I have added another foot of topsoil to thier field and still have unacceptable leakage points on the down hill side. The salvation of the system comes from the artifical wetland. The effuent that enters the chambers is about 98% treated, so what leaches out of the chambers(and sometime to the surface) is not considered a health hazard.Dave

          18. Ralph27 | Jan 20, 2002 05:40pm | #22

            *If the venting is properly installed and there are no leaks, or you fix it, and you still have septic smells outside, I recommend an aerator. I know it sounds like it would just make it worse, but I have never had any smell problems on any house that has had one. I was told that the aerator is the reason by a plumber. The drawback is that it is one more thing that can break and you do need to clean them. I have this done with the pump out. Just a suggestion, ask your plumber about them in your area.

          19. Ted_LaRue_ | Jan 20, 2002 09:48pm | #23

            *Actually, ADS is just the name of the company that makes it. I think the pipe itself may very well be ABS plastic (it's black, anyhow).

          20. Ted_LaRue_ | Jan 20, 2002 10:16pm | #24

            *Dave, I guess all systems are going to require some permeable soil around them. The installation instructions specify a 3' wide trench for the 3' wide chambers, with 12" cover fill. But if the soil you're installing in won't perc very well, I think any leach field type system will have problems.I installed that Infiltrator system with no problems, and I've driven a farm tractor with a backhoe on it across them with no problems. They claim the chambers can take a load of 8 tons per axle, but I certainly wouldn't test that. Maybe the strength of the chambers varies with brand? One disadvantage to the system is that the lines have to run pretty nearly straight because of the 3' width of the pieces and the way they snap together. If following the contour on a slope, that can be difficult.

          21. josh | Jan 20, 2002 10:52pm | #25

            *from what i have read some people are responding to a problem of smell outside, and your question was in relation to smell inside. We had a house with the same problem, passed code and everything, but one of the bathroom waste vents was lower on the roof then an exsaust fan vent ( air) when there was no wind and the fan was not on the stink entered the house that way. When we thought this might be the problem we put a temporary vent extension on the lower waste vent. smell was gone.temporary became permanent.BTW the exsaust fan di have a flpper but the stink would still get in.

          22. splintergroupie_ | Jan 20, 2002 10:59pm | #26

            *The odors from my vent stacks also got pulled inside my house by prevailing wind currents creating relative vacuums on the lee side of the house, so that the odor came in through a door there. This also happens when i burn wood, though that chimney is well above surrounding surfaces. At least when the fire is going, the door is usually shut.

          23. Martagon_ | Jan 21, 2002 06:29am | #27

            *Are you sure that it's from the septic system??? For the past, oh probably 10 years, there has been an occasional horrible smell in my Mother's house. We always thought the same thing - septic smell. This past week (notice above, it's been about 10 yrs) my brother was cleaning out the basement, and found a bag of malathion (insecticide) that my dear Father had put downstairs for some unknown reason. It should have been in the barn, but he brought it in and shoved it under a work bench. We never really took note, maybe it was damp weather when it smelled, but just always figured something that stinky had to be the septic. I was thinking dead animal caught in the framing, but three years is a long time for a dead animal to smell. Or a really large animal. Were you rude to the builders, and they're getting their revenge. (just kidding, guys.....) Is there anything else that could be causing the smell? Is the ground over your weeping bed spongy and damp? Are you being mean to your septic system - - we've had this discussion before, on what you can and cannot put into it.

          24. Jerry_Albrecht | Jan 21, 2002 10:03pm | #28

            *We have a similar problem with my mother-in-laws cottage. She has an engineered field with a sewage pump. The field is 25' higher then the tank. Our problem stems from the fact that there's a vent at the pump tank which is tandem to the septic tank. It's just a short piece of PVC with a couple of 90's on it. You really notice the smell when the pump stops running and the liquid in the line runs back to the tank. Wouldn't be so bad but it's in the front yard. I suppose we could get a flag pole and run the vent to it.

          25. Wayne_Law | Jan 22, 2002 01:07am | #29

            *Boss, thanks for the support, but I kind of like Ted's idea (#7). It clearly could result in odor if the trap is not installed. I've never see a system without one, though, I don't make it a habit of looking at septic tanks!Good luck, Hoov.

  2. Hoov | Jan 22, 2002 01:07am | #30

    *
    My house was built 3 yrs. ago and since day 1, we've had septic odors outside. For the first 2 yrs. we convinced ourselves it was a neighbor's house, but it has gotten worse over time. Our septic tank is only about 8" below ground (we know the exact location due to the rectangle of dead grass), so we thought it was from that, but recently we'd noticed it in the attic (badly). So now we think it's the vent system. Any ideas on fixing this problem, assuming the vent system was installed properly? Does it perhaps have something to do with winds and the gases settling to the ground?

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