Plumbing Smell Mystery

[Axolotl]

We had a new septic tank and drainfield installed last fall. Ever since then we have had a VERY strong sewer smell coming from our drains and from the vent pipe on the roof any time we run much water (shower, laundry, etc). I thought the smell was coming from the new tank, so I opened the cleanout (on the drainline between the house and the tank) and left it open. Little or no odor seems to be coming out of it, even when we smell it in the house. It's almost as though the smell is coming from the plumbing inside the house, but we aren't sure how that could be possible, or why it would be happening.

1. What is causing the smell?
2. Why did it start when we got the new septic system?
3. What can we do to get rid of it? It's quite overpowering both inside the house and out.

 

[havasu]

I wonder if a critter crawled inside your vent pipe and died?

 

[Axolotl]

I thought of that, but it seems like the smell should have gone away by now. It's been happening for 8 months. Also, there is no smell when water hasn't been run for a while. I've looked in the vent pipe from the top I didn't see anything there.

 

[LiQuId]

i assume you have traps on all your fixtures and not one primary building trap installed?

.. Could be a blocked vent ( rare ) or an overgraded pipe forming a syphon.

or perhaps a hole in one of the baffles inside the tank, It could be many things but if it happened when the new system was installed the company that did the installation should be responisblle for fixing the problem they created ( if it WAS them who crated this problem )

Im no septic expert so I'll be keen to see what those specializing in these systems suggest.

 

[KULTULZ]

DISCLAIMER-

I am in no way that knowledgeable, but while recently carousing with my browser came across this-

Vent pipe filters that eliminate or lessen bad foul septic tank or cesspool odors. Septic tank odor is a big problem for some homes with septic tanks. Put these filters on your waste stack exhaust and hopefully it will lessen the stinky pipes.

I had a home (new) in NC years ago that displayed the same problem and was researching it as I am buying a house in WV with septic. It is unpleasant....

 

[Axolotl]

Thanks for the replies. I opened up a wall and did some hunting today. It appears that our shower drains do not have traps, and the washing machine drain doesn't either (house was built in 1976). As a test I've put tape over/around all the trapless drains and it seems to have helped. Looks like we could be in for some major plumbing work to add traps, as our concrete slab construction is pretty limiting.

Regarding the filter that can go on the top of the vent pipe- we tried one of those last Spring. It reduced odor at the vent, but immediately made it worse inside the house. I assume it forced the gas into the open drains due to the increased air resistance on the vent.

We're still curious why this didn't happen with the old septic tank/drainfield. Someone said the new tanks are more efficient, and that therefore they produce more byproduct gas. Could this be right? If so, even after we fix the drain traps we will still have a terrible smell coming from the outside vent. Is there any thing additional we can do?

 

[johnjh2o]

Once you get the trap problem resolved then try extending the vent on the roof. This may get it above the air currents that are forcing the odor down.

John

 

[Axolotl]

I'm not sure a few extra feet of vent pipe will help. The smell fills our entire driveway area and the yard on that side of the house. How much taller are we talking about?

 

[LiQuId]

As far as the traps on the fiztures....

You could

A. install p traps on all the fixtures. ( and Yes the lack of p traps was for sure the problem )

B. install a building trap ( this involves some gradework and possiblly opening up the slab and is best done by a professional )

as far as the Efficianccy of the new tanks, I believe it possiblle.

extending the vent a foot is cheap and easy, I would give it a shot firstly.

I believe that if you were to install proper traps that this odour problem wild minimize itself. Currentlly the air is circulating and free to do so between the fixture drains inside the house and the roof vent terminal which will liekely entrain more air from your septic tank. You could test this theory by plugging all drains in your house, ( dont forget about waste overflows ) and giving it a few hours to sit and settle. the smell should be better as the air is no linger free circulating between the fixtures, tank and vent terminal

Let us know if this works.

 

[johnjh2o]

As far as the traps on the fiztures....

You could

A. install p traps on all the fixtures. ( and Yes the lack of p traps was for sure the problem )

B. install a building trap ( this involves some gradework and possiblly opening up the slab and is best done by a professional )

as far as the Efficianccy of the new tanks, I believe it possiblle.

extending the vent a foot is cheap and easy, I would give it a shot firstly.

I believe that if you were to install proper traps that this odour problem wild minimize itself. Currentlly the air is circulating and free to do so between the fixture drains inside the house and the roof vent terminal which will liekely entrain more air from your septic tank. You could test this theory by plugging all drains in your house, ( dont forget about waste overflows ) and giving it a few hours to sit and settle. the smell should be better as the air is no linger free circulating between the fixtures, tank and vent terminal

Let us know if this works.

A house trap would eliminate sewer gas from entering the building but most codes no longer allow them.

John

 

[LiQuId]

very true.. ^

Axoloti, what are your drains made from ?

I concluded that in the original septic tank the building drain likely terminated into the tank with a 90' bend. and that your new tank was prolly installed with a t-wye, allowing the septic gas to migrate.

if this is the case ( likely imo ) it could be very serious, as the gasses from a septic tank rapidly breakdown Copper DWV piping. i suggest looking into or contacting the installer to fnd out exactlly how the tank was installed, if you have Dwv copper in your house, they SHOULD have known better.

 

[Axolotl]

Thanks again for the replies. I tried putting tape over all the drains for the last few days. The smell in the house is eliminated. However the smell outside the house remains.

Regarding the house trap, what happens to the buildup of gas in the septic tank? Where does it go?

Regarding the copper pipes, we have a mix of PVC and metal. It looks like mostly PVC, but with some metal sections connecting to the tubs. I need to open up a wall further this weekend to verify.

 

[LiQuId]

the smell will remain inside the house untill you install traps.

The house trap is ( as mentioned ) not legal code ( was okay for a long time and certain places allow it )

the septic gasses in a tank are caused by anerobic bacteria.. that is bacterial that thrives in a moist, dark enviornment. they are always present and work to break down the organic matter in the tank, the should stay in the tank however.

if a septic tank is installed with a t-wye fitting the gasses are free to migrate through the plumbing drainage system, which, If you have copper piping components, will quickly attack those components, and will absolutely be more smelly out of the roof vent.

the same system installed with a 90 temination at the tank will not allow free migration of the gasses and will better contain them and not allow them into the homes DWV system and, as such will not be able to attack copper components inside your plumbing system, and the only smells that would escape your roof vent would be those from organic materials ( poop and such ) inside the homes drainage system, which you wouldnt smell inside because you would have p-traps installed to prevent the gasses from coming out.

what likely happened is the company installing the septic tank Recieved a t-wye fitting, and without much thought they installed it without considering the homes drainage system. I would contact them and ask for information pertaining to this but do so kindly, I dont believe that a company would intentionally do this connection wrongly... likely an oversight that unfortuneatelly is causing you some un-plesantness.

do you know the model of the tank installed ?

the smell inside the house will dissapear AFTER you install p-traps on all the fixtures. ( it will be similar to having them all covered with tape. ) on the whole, the smell will be remedied when the tanks connection problem is solved. ( remeber I am taking an educated guess on that, i really dont know what else would cause such a strong odour from a tank )

hope this helps, and Please DO update us on what you find out as we have invested some time to try to assist you and are not seeking a payment other than a thank you if our advice helps and the knowledge that we correctlly assesed the problem and solution .

 

[LiQuId]

HowStuffWorks "How Sewer and Septic Systems Work"

theres a link. you can see in the picture below the video that this tank is installed with a T-wye So the gasses at the top of the tank can migrate back through the plumbing system ( this is what I believe is happening in your home ) imagine now I one were to cap the top of the T-wye in the inlet of this tank.. the gasses are now contained to the tank .

 

[KULTULZ]

DISCLAIMER-

I am in no way that knowledgeable, but while recently carousing with my browser came across this-

Vent pipe filters that eliminate or lessen bad foul septic tank or cesspool odors. Septic tank odor is a big problem for some homes with septic tanks. Put these filters on your waste stack exhaust and hopefully it will lessen the stinky pipes.

I had a home (new) in NC years ago that displayed the same problem and was researching it as I am buying a house in WV with septic. It is unpleasant....

Additional Info Someone May Find Helpful-

I came across this while CAROUSING WITH MY BROWSER

and thought it might be useful to someone-

Odors are a big problem for some homes. Vents on the roof allow the pressure to equalize as waste water flows down through the drain pipes, without a vent system your sinks/tubs/toilets would gurgle, glug, and drain slow. Often these problems are caused by wind currents. As the wind blows over the house, the air currents that are supposed to carry the gasses up and away can carry the sewer gasses down into the living areas.

The SWEETAIR filtration device is an activated carbon filter that can prevent this problem by removing the offensive odors as they come out of the vent. They cost about $50 and most homeowners can easily attach the filter themselves in minutes.

They can last 20+ years and as an added bonus, they prevent birds, squirrels and leaves from clogging your vent stack (I once found a HUGE gray squirrel in my toilet that had crawled into the vent/plumbing system from the roof.

Luckily I looked before...well, you know. I now have a vent filter to prevent future intruders...true story). Call Sweet Septic at 1-800-622-8768 or visit their webpage at Sweet Air™ | Put a STOP to Septic odors! (800) 622-8768.

Sourced From- Septic Protector

 

[phishfood]

That notsosmiliesmilie is friggin' hilarious.

 

[havasu]

Right click, save. Thanks!

 

[Axolotl]

Please DO update us on what you find out

UPDATE: After opening up several walls and having a plumber do a smoke test, we discovered that all the drains had traps, but two drains were vented incorrectly and one wax ring had failed. The washing machine and one tub were both connected with the vent on the wrong side of the trap, so they were sending sewer gas straight up through the drains.

Now that those items have been fixed, the smell in the house is gone. The smell outside the house has been greatly reduced, I assume because the airflow through the system has been reduced by fixing the vents. We'll see if it's tolerable over time. If not, we'll try a charcoal (activated carbon?) filter on the vent pipe on the roof. We had tried one in the past, but with the vents being wrong all it did was force more sewer gas into the house.

As for why we never had an odor problem until the new septic tank was installed, I think whoever suggested that the new tank had a "y" (wye?) inlet was correct. The old tank was from the 1970s, so it probably didn't allow gas to escape up the vent.

Sooo... mystery(ies) solved! Thanks to all of you for your time and expertise in helping with this situation. I really appreciate it.