Smelly Gooseneck Septic Vent Pipe

Fill the 'gooseneck' (trap) with water. It has all evaporated away, and must be filled again. There is (probably) a screen or cap on top to prevent birds/debris from entering the pipe... remove it, and fill with water, and replace the cap. One can also use cooking oil (but you did not hear that from me).

Thanks so much for your response. We have heard that the reason the pipe is goosenecked is to prevent water from entering the system....There is no cap just the curved pipe. Should I just be running water down into the pipe?

Hell ckoz.

This gooseneck... is it a vertical pipe up from the tank, then a 180⁰ turn to vertical (down), then another 180⁰ turn to vertical up again (an 'S' shape)? If yes, the following is applicable:

No, the purpose of the gooseneck is to trap water; this allows the tank to exhaust or intake air as required, the offgas or fresh air simply bubbling past the water. The water serves as a barrier to the free transfer of gas (smells, in this case).

Yes, just run the hose for 5-10 seconds into the pipe.

There also may be the case that the digester (for one reason or another) is just very active. In that case, the smells will persist, because the gas is pressurizing the vault/tank, and will push past the water in the trap.

NOW, this gooseneck... is it a vertical pipe up from the tank, then a 180⁰ turn to vertical (down), and that is it (an upside down 'U' shape)? If yes, the following is applicable:

Yes, the purpose of the 'gooseneck' is to prevent rain and debris from entering the tank. If the offgas is coming from this setup, there is not much you can do . Do not fill up with water, there is no place for it to collect.

You could fill it with water and add just a small amount of oil (which will float on top of the water) to slow down the evaporation of the water.

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Aren't septic tanks supposed to be sealed with no vents? This is the info I got from our pump out guy as I had been leaving the tank cap exposed (not covered with soil).

Pump out guy said that a septic system is supposed to be "closed system" for the microbes to break down the waste this being the reason ours had to be pumped out every year when we noticed it overflowing.

Since covering the cap with soil (about 16 inches), it has been three years with no pump out.

Maybe just coincidence, I dunno?

Gooseneck vents like mine are seen on all new systems in our area (New England). They are for allowing air into the system to prevent unwanted growth in the pipes in the leach field. Seems like the smell indicates some sort of problem.

Yes, a typical septic tank (single stage) uses anaerobic digestion, then leaches directly to the drain field. There are some that use a two-stage process, where the effluent is aerated before seeping.

OP tells us there is a vent. I do not know where in the world OP is at (Oz?), and USA practices may not be in place where he is.

As with you, I dunno. If a vent stack with a trap is visible, and the methane, ammonia, hydrogen sulfide (and the other yummy smells) are evident, I would say fill the trap with water. With information in OP stating the trouble is new, that is probably the source.

ckoz and Doorman - I was not aware of more than one type, very interesting.

That having been said, then I have to agree with everyone, fill the trap with water/liquid. Seems like a reasonable explanation/fix to me

It is a 180 degree upside down u shape but it is in the field at the end of the septic field not close to the tank...

OK then. It is a breather for aerating the effluent.

You can help it a little bit by modifying the pipe pointing down to be a pipe pointing up. This will form a trap for the gas. Two 90⁰ street el's and a short (1' or so) length of pipe, all these the appropriate size to match the vent.

In this circumstance, you do not want a lot of water 'head', so keep the distance short between the existing elbow and the new fittings.

And (this is important!), ONLY glue the NEW pieces together, and friction-fit the new pieces (when assembled, it will look like a 'J') into the existing downturned elbow. It may leak a little but that is OK, just fill again. If this leaking is objectionable, glue a threaded union in there, with the joint between the existing pipe and the new stuff. DO NOT FORGET to remove this when it gets cold... the water in the trap will freeze, and there will be more troubles. This is why it was not assembled this way when you bought the house. Save the part for next year.

Then, have fun at your party!

Thank you so much...you are really helping us sort this out. Keep you posted....and thanks for your good wishes for our party!

YIKES!!!!

Ummm one more question. You said the fitting may leak....am I filling the "up" part of the fitting with water or are you just talking about the water that may accumulate from rain?

The fitting itself will not leak; if you select the friction-fit method, the joint between the existing down-facing elbow and the new quarter-turn to horizontal elbow may (no sense kidding anyone, it will) leak. This may not be an issue; does the smell interfere with daily life at home? If no, just add water to the trap whenever outside at the picnic table. If yes, then use the union suggested. This should be good for an entire season. And yes, after assembly, pour a couple of quarts of water into the trap from the new vertical standpipe. I cannot emphasize enough: DO NOT leave this attached in winter.

Regarding rain collection: I would not bother with it, but if concerned you can buy two additional elbows and reproduce the original 'gooseneck' configuration on the top of the new trap. Vault volume increase from rain would be negligible, and the trap will catch debris (this being cleaned out in the fall).

I should say again, this should help. I doubt it will completely remedy the problem. As the influent does the anaerobic dance, there is an offgassing. This MUST go somewhere, and it will pass thru this trap (better there than in the house, eh?). This arrangement will help to reduce the releases, but when pressure builds, it must go somewhere.

I think "Just an Engineer" (Post #14) is correct.

A well operating septic doesn't generally cause odour issues.

When a septic starts to be noticeable by its smell, is an indicator that the system is not functioning correctly.

It requires bacteria to break down the effluent within thwe tank. If something kills all or parts or the bacteria, then the process starts to smell.

As "JAE" stated, bleach, antibiotics etc can upset the balance.

A work mate even noticed a smell in his system, and discovered that one of the family had been using an antibacterial mouthwash and spitting the residue down the sink. This was enough to upset the balance of the system.

So, I'd be working out what's going down the drain! Or what is new, thats going down the drain.

tony

Thanks.....guess we are going to have someone come and look.

http://www.stopsepticodor.com/. This is just one. There are many activated charcoal septic vent covers on the web. I just posted this one because it mentioned yard based vents. Apparently this is a fairly common problem.

Also, it looks like if your vent hole is pointing down, you will need to cut it off first so you have straight pipe coming from the ground. The vent filter itself will prevent water from entering.

When my friend constructed new house he was advised to fill the sceptic tank partially with common salt for bacteria growth which digests the sewer content. I dont know if that may solve your problem. Please check up with local municipal authorities.

Most homes in New England have vent pipes installed through the roof of the house. That location allows the gasses to disperse and not bother the occupants. Been done this way for many years now. I have seen some of the traps that you describe on commercial sites but not on many home sites. You might investigate the possibility of adding to the length of the pipe, raising the inlet/exhaust point above the ground by 10ft or so.

Every house I've ever seen is vented through the roof. I've never heard of venting a leach field. I can only guess it has to do with poor perculation, and allows some of the water in leach field to evaporate to the air.

If the suggestions to restrict gas flow out of the inverted U bend are followed then the gas will have to find a new route to escape - which possibly be via one of the connected sinks, toilets or whatever in the house.

Good suggestions - move the stink indoors!

ckoz

The inverted U pipe is a vent to allow the septic system to work properly. Gases of methane, H2S, CO2, N2 build up and prevent the flow into the tank from the house if sufficient gases become present. Do not block this vent or the problem may well back up into the house by making the sewer drains (toilets, sinks) seem plugged or slow.

If the vent is at the end of the tile field, try burying an extension of the pipe and raise it at a fence line where it may be less noticeable. Hydrogen sulfide is the gas that will give you the smell (rotting eggs) and is slightly heavier than air. It will sink to the lawn on a still night and give you the headaches of odours. By the way these gases will be found in tile beds and should be expected. You can raise the vent as high as you like without causing a problem.

I have seen such vents installed on the septic tank or very close to it but never at the end of the field. It should not be a problem at the location and is likely there to get away from the house. It seems you need to move it further and higher. You can try venting it through a bed of AC media as Kamarat suggested.

I am guessing that there is a large clay factor on tile beds in your area and problems with flows. In areas of sand there is generally sufficient venting from the tile bed. Anyway that is the purpose of the vent but you will have to direct where to vent. You could try returning it to the house and above the roof (still might be an issue on still nights). I do not think you have a tile field problem on a 4 year old house.

The main question I have is: where is this gooseneck vent located, at the septic tank roof or out in the "leach field"?

A septic tank doesn't need a vent of any type whatsoever because the microbial process in the wastewater is ANAEROBIC, meaning the "bugs" do not require oxygen to metabolize the waste. The wastewater nutrients are digested at a much slower and thorough rate. If the vent is tied into the septic tank my recommendation is to remove it and patch/plug the hole in the concrete lid.

If the vent is located in the leach field then there may be a reason for it being there. Case in point: if the subsurface wastewater disposal system is a built-up or mounded system or a sand filter type system (can have mounded or even flat surface), then the vent is warranted because the AEROBIC microbes inside the sand filter require additional oxygen (via the vent) to aid in the digestion (ie breakdown) of the wastewater leachate that exits the septic tank. Typical shallow absorption trench systems (ie leach field) do not need a vent of any type whatsoever because the aerobic bacteria can live and thrive by the vary nature and construction of the trenches: they are shallow and allow air (and hence oxygen) to enter into the soil. If you have the typical absorption trenches, then you don't need a vent!

Good luck!

And a dry well needs a vent.

If it is giving off a bad odor - it sounds like there is a gas buildup. Plugging that will most likely not solve anything.

Better to talk to a local that knows how the systems in the area are typically set up.

#9 from OP

"It is a 180 degree upside down u shape but it is in the field at the end of the septic field not close to the tank..."

You are correct in that the septic system is a two part with an anaerobic digester called the septic tank followed by a leaching bed but that is usually aerobic. The tile must drain freely by gravity through the soil it is built on and it is expected the soil has suitable porosity, an aerobic factor. The tile field will receive the gases (CH4, H2S, etc) from the tank created by anaerobic digestion or else the gases will buildup ( it would be expected some gases would be trapped, particularly in winter ). My own septic system is not vented but it is raised and built with imported sand. It is uncommon to see vented tanks on domestic systems but they are often are used on larger systems. My brothers house in southwestern Ontario is vented to allow better drainage as are most in his area. Perhaps OP should get a copy of the permit to view the reason for the vent. I can only speculate but I do know if sufficient gases are allowed to build up there can be problems within the house with plumbing drainage. However, I agreed it is not typical for residential use.

The only reason I can think of attaching a air vent (gooseneck) to a septic tank is to aid in hydraulic flow of thee waste.....you need atmospheric pressure for the liquid to flow under gravitational means, ie, need a positive head. Since most residential homes have a vent stack incorporated in the house internal waste piping there is no need to include the air vent at the septic tank. If there's no vent stack inside the house (usually through the roof, but sometimes out through an exterior wall which IMHO is a NO-NO), then the waste lines can become vacuum-bound is a sense.

I see no reason to vent septic tank gases as the bacteria in the waste (and sludge)are anaerobic, and those gases that you mention will not harm the bacteria nor minimize waste synthesis.

===CaptMoosie, LPE

Sorry to keep expounding on the vent but there is an aspect you are still missing.

If the gases are trapped in a septic tank, the pressure in the tank will be somewhat above atmospheric. The conditions when this could happen is when the influent is greater than the effluent. Such a condition could happen in heavy soils with high t times and an undersized tile field. The stack in the house will allow the air displaced by toilet flushing or tub draining to escape and allow gravity flow. However, the outflow will be retarded by the extra pressure in the septic tank. We could then have a condition where the influent into the septic tank is slightly greater than the effluent. A backup in the house plumbing is then possible and will be reflected in the lowest fixture in the house with a drain. The vent on the tank will aid the influent by not providing that extra pressure within the tank to buildup. I have seen such conditions but never on a raised tile bed. OP has a new septic tank and is in an area where the venting of tanks is common. The practice suggests that the installers are aware of a problem and know the correction. OP may need a larger tile bed but the existing one must have been allowed by the local inspectors.

Of course if the tile bed is waterlogged such conditions of influent exceeding effluent are also possible. That is when you are in a major repair to upgrade the bed. I would hope that is not the case in OP's new system.

The original point was about a stink and how to get rid of it so it is talking about a situation in hand.

Office engineering vs. field I guess one might say.

I heard hundreds of times from the office that what was happening in the field couldn't happen - all the while I was standing there watching it happen.