Sewer & septic gas & odor questions & answers:

These questions and answers address common questions about the source or cause of septic system odors or smells & suggests what to do to stop the problem.

This sewer gas smell article series describes how to get rid of or cure odors in buildings including septic or sewage or sewer gas smells or "gas odors" in buildings with a focus on homes with a private onsite septic tank but including tips for owners whose home is connected to a sewer system as well.

Septic System Gase & Odor FAQs

These questions & answers about curing septic system odors, smells, gases, backdrafting were posted originally

at SEPTIC SYSTEM ODOR CURES - be sure to see the septic system or septic tank odor diagnosis and cure advice given there.

On 2019-08-10 by (mod) - When a soakaway bed is smelly

Anon

When a soakaway bed is smelly I suspect that sewage effluent is near the surface and the system is failing.

Before trying to fix anything let's get an accurate diagnosis of what's wrong.

A thorough inspection starting at the septic tank (normal sewage levels? damaged baffles? Other trouble signs), and the distribution box that distributes effluent into the soakaway area and then the soakaway itself are what's needed.

Let me know what you're told and we can comment further.

On 2019-08-10 by Anonymous

How can i control sockaway odour

On 2018-12-02 by KC

HELP! My son had a new septic system put in 2 yrs ago, along with some new plumbing to accommodate but has a sewer smell in his house ever since that I have pinpointed to a specific area in the basement - a room under their hot tub.

The one drain in that room does have standing water in it and supposedly proper venting has been done for the new plumbing and the pipe outside is not plugged and yet a sewer smell persists and is stronger smelling in the winter time. I am worried for their health and they have become nose blind to it!!

On 2018-06-17 by Anonymous

Only smells when waters going in the septic from doing laundry or flushing. Had inspected and drained 6 months ago... last 2 months it smells when water goes in it

On 2018-02-13 by Duane

Thanks for the information

On 2018-02-13 by (mod) - Septic tank pumping would not be expected to cause a sewer gas odor indoors

Duane

Septic tank pumping would not be expected to cause a sewer gas odor indoors unless there was an unusual event like a broken-off septic tank inlet or outlet tee.

I'd look for odors at a floor drain, then for a defective plumbing vent pipe system - perhaps you'll need the vent piping pressure-tested.

On 2018-02-13 by Duane

We built a new home 5 years ago we had our septic pumped out in November now whenever we use water no mater whether it’s a shower the toilet or wash machine there is a smell in the basement doesn’t seem to come from the toilet or the drain downstairs but it’s in the main room any ideas?

On 2017-10-11 by (mod) - awful smell outdoors from the vent stack pipes

Dave
your question and our reply were also posted at https://inspectapedia.com/septic/Septic_Odor_Cures.php

On 2017-10-11 by DaveQ

We moved into an older house, '67, on a septic gravity system that required a new inlet baffle because old cement one fell into tank.

We were getting an awful smell outdoors from the vent stack pipes and installed odor hogs. Since, we have been getting sewer smell in the upstairs bathroom when we shower downstairs in the daylight basement. It appears that the smell is coming out of the bathroom sinks above but they both appear to have properly installed p-traps?

On 2017-05-06 by (mod) -

If you are connected to a public sewer then I suspect a back up in the sewer system, or your sewer line connection between building and public sewer is blocked or backing up.

If you're connected to a private septic system there could be other problems such as a blockage in the drain field or a failed field.

On 2017-05-06 by Rod

My outdoor sewer is bubbling water. Any ideas what could be the issue?

On 2017-04-30 by Kelly

We lived in a house with septic tank system. The tank got pumped out when we moved in. We replaced all toilet washer rings and checked there are u tubes at all flushing points. There is no backup nor smell outside or in the basement. However a couple of days after it rains, especially on a hot steamy day, there is rotten egg foul smell. The sinks don't usually smell. I tried rid-x and buttermilk, it does not help at all. We never pour grease or use house cleaning chemicals into the drain. The house is a ranch 8 feet ceiling.

On 2016-12-15 by Lucy

We have a holding tank that once in a while there is an odour back up coming from our bathtub drain.

We run the water, but that doesn't stop it, and then suddenly it goes away and it may be months again before it happens, or could be the next day. No smells in the crawl system or in the other bathrooms, always from the one bathtub only. We have a vent on the roof. Any thoughts on why it comes and goes.

On 2016-10-13 by R.Srinivasa Rao K

We have occupied a new house since 2 months. Whenever we flush the toilet after use we get a very bad smell outside during the discharge of the sewer water. I verified the inlet and outlet of the septic tank through inspection chambers, there are no blockages. Please suggest me the remedy.

On 2017-09-17 by (mod) - how to get rid of vent pipe odors blowing down into yard

Lisa:

The sewer stack vent smell problem you describe is one that a number of readers have reported. Often the problem is traced to specific site conditions, prevailing wind direction, roof slope, microclimate - all things difficult to affect.

Extending the stack upwards and installing a wind-operated vane type cap that keeps the stack opening pointing downwind can help.

Adding bacteria to the septic tank is in my view

- never a suitable long term remedy for an odor problem that has its roots elsewhere - septic tank odors need to be properly directed

- doesn't distinguish between the fact that it's normal for a septic tank to smell and abnormal for those gases to discharge into occupied spaces

- makes money for the additive companies but isn't the best investment for a homeowner whose drain waste vent piping may need corrections

- is not recommended by any scholarly research nor expert on septic system design and function (with exceptions of some special additives or disinfectants on some aerobic septic system designs) -

see SEPTIC TREATMENTS & CHEMICALS

A look into the septic system for normal levels in the tank and in the D-box would be in order as would an extra check that there is no sewage effluent leaking into the yard surface.

For other readers, the Odor Hog is a septic vent cap and charcoal-vent filter sold by Odor Hog, a Tucson AZ company, website https://odorhog.com

My OPINION is that the ability of the drain vent stack pipe cap provided by the company might itself be an important aid in reducing the effects of wind on downdraft problems in some DWV systems.

Building owners/occupants who experience drain problems such as noises, slow drains, or trap siphonage are generally advised to check for a blockage in the vent system as one of the steps in debugging those problems. If a drain vent pipe filter slows or blocks the venting of sewer gases that might contribute to the problem - something easy enough to verify by temporarily removing the vent cap and filter.

On 2017-09-15 by Lisa Kaplan

We had a new septic system put in a month ago. The gases coming out of the vent stack on the roof are horrific and smelling up the yard. We purchased an odorhog and that has helped slightly. Our installer said that once the bacteria in the tank get going the smell should go away. Do you agree? If yes... how long does this usually take?

Reply by (mod) increasing sick smell from laundry room

Ian,

I would look for

- improper drain trap or venting

- a dead animal in walls or ceiling

see ODOR DIAGNOSIS SIX STEPS

On 2017-09-14 by Ian

New purchased house in the country, march 2017, there has been an increasing sick smell coming from the laundry room,

so bad now we have had to seal off the room and use a fan to suck the air out of the room through a window. still a heavy odor outside the room and outside the house. what do we do?

On 2017-09-02 by letlapa

Theres a back feed of gases in the drainage system particulaly during the night but everything is working well beside gases

On 2017-08-23 by (mod) - unsafe sewer gas odors in laundry & bath

Dale

At https://inspectapedia.com/septic/Sewer_Gas_Odors.php SEWER GAS ODORS - we list some of the dangers of sewer gas - you might pass that on to your landlord.

You might try point out some of the safety steps for methane or sewer gas odors

at SEWER GAS SAFETY STEPS https://inspectapedia.com/septic/Sewer_Gas_Odors.php#SewerGasSafety

And as the landlord says she can't find anyone to fix the trouble, you may have to be the one to call a plumber. Or your health department.

On 2017-08-17 by Dale

Septic gas odors in our laundry and bathroom, unbearable at times. Worried about harm to my children. Live in a rental house, landlord says can not find anyone to fix this problem. Going on well over a year now.. Worried... Can you help?

On 2017-07-02 by melva saez

why if we have anew septic the odor still inside the house

On 2017-06-21 15:50:17.784043 by (mod) -

I will start by dragging down with the owner is most strong.

for example if that is in a bathroom, it's possible that even though you've done repairers, a toilet is not properly sealed or there is a dry plumbing trap.

On 2017-06-21 by Debi B.

Just had a new septic tank and drain field put in, in January. Living in Florida, we began having large amounts of rain. When that happens, we get a sewage smell from the master bath toilet We "snaked" the roof vents, made sure all the toilets have been flushed and water in the bowls, and just had the toilet sealed in December

. Why are we still experiencing this odor? The company that put in the system were out last week but didn't really offer any solution. Should I continue pursuing this matter with the company? Help!

On 2017-05-06 by (mod) - smell coming from the toilet

Michaela

Some things to check:

1. very thorough cleaning around the toilet, on all nearby surfaces: toilet base, bowl exterior, bowl interior, floor around toilet, nearby walls

2. leaks around the toilet base from a mashed or leaky wax ring seal between toilet base and top of the waste pipe flange. A plumber may have to remove the toilet to inspect and make this repair.

On 2017-05-06 by michaela

@Debra,
Hi debra i am having the same issue with the smell coming from the toilet!! Whe have just moved into a rental and its our first experience with a bio system.
Did you happen to find out the problem?

On 2017-04-19 by (mod) - leaks and odors often traced to toilet wax ring seal

I would start by asking a plumber to check or replace the wax ring that seals the toilet to the waste pipe.

On 2017-04-18 by Dorothy

We have a septic tank that sets away from my Manu. home... The smells seems to come from the toilet area...Why is that? and what can I do to stop this nauseating smell in my house.

On 2017-04-11 by Debra

We have a septic tank and just started smelling a bad order in the kitchen drain what can we use to deoderizer to stop smell

On 2017-03-06 0 by (mod) - bad smell in bath room

Use the bathroom exhaust fan, or open a window if it's a normal human odor.

Check for dry traps at sinks or showers or tubs
Check for a loose or poorly-sealed toilet

On 2017-03-06 by Steve

I have got a bad smell in bath room

On 2017-02-18 by (mod) - use of upstairs shower makes downstairs terrible smell

Diane
at https://inspectapedia.com/odor_diagnosis/Index_Building_Odors.php you'll find a number of diagnostic articles on this sort of odor issue.

If you have absolutely ruled out a blocked or partly-blocked sewer line then the problem may be in a vent or the venting system.

I'd start by looking for floor drains or plumbing fixtures on the floor where the odors are worst.

On 2017-02-18 5 by diane

when we shower upstairs the smell of sewer downstairs ir so bad you cant go down there

we have changed our septic system dug up basement floor to check for cracks on the pipes but light down in vent to check and its driving us nuts we still cant find the problems cna someone help

On 2017-02-02 by Fred

I had the septic tank pumped out and now my house stinks.

On 2016-11-22 by Suzanne

We had our leach field replaced exactly two years ago after it had been failing for about a year, with a damp area about 25 ft from the house.

During the winter melt the year before the septic backed up into the basement bathtub. The land all around here was saturated so we didn't act on it yet.

But when it did it again when winter was setting in, we had the leach field replaced, not the tank which the contractor inspected and said was fine. Ever since getting this work done, however, there is a rotten egg septic smell when we walk up the deck steps and pass the area on the roof where the stack is.

The odor is slight but definite. It started right away after the leach field was replaced and is more pronounced in cold or wet weather.

The contractor blew off our concerns and I have been trying to find out what could be wrong. I reindeer if a vent got clogged during the backups?

There is no smell emanations over the tank and the leach field is dry. One drain in the house seems a little slow. We live in a split so there is a bathtub and sink that drain a little low. The slow bathtub is upstairs. Suggestions?

On 2016-11-18 by Mod

David: look for a defective check valve and improper venting at the sewage ejector pump pit

On 2016-11-18 by David gas relaease when sump kicks on

We have an unusual issue I've not seen addressed anywhere. We have a bathroom basement with a sump pump and our entire house is on a septic tank

. Each time the sump pump kicks on, the toilet in the master bath directly above bubbles up sewer gas. We called a plumber when first noticed this problem, and when he dug up the access point to the septic tank, it released a lot of gas, and relieved the pressure.

The problem stopped for about 6 months. But the problem is back again, and I don't relish the thought of digging up the yard again. Anyone have any other solutions for our sewer gas problems?

On 2016-09-28 by (mod) - not enthusiastic about septic tank treatments

Marke,

One of the many reasons I'm not enthusiastic about septic tank treatments is that they become a permanent conduit of money out of one's wallet and into the septic tank, often with little or no benefit.

Is it feasible to either extend the vent upwards or horizontally then upwards so that the discharge is nowhere near the home?

Also:

Three months of wastewater, even for just a couple of people, is a tremendous volume - more than would fill a 1500g septic tank. What's happening to all of that volume ?

On 2016-09-27 by Marke - replaced septic system with holding tank, sewage smells ensued

we live on a hill and there was apparently an issue with the septic flow field years before we bought our home.

The septic system was replaced with a holding tank, which gets pumped every 3 months. Regardless of how full or empty the tank is, we constantly have a sewage smell outside the house near the tank.

We had it inspect d and there is no damage to the tank. It seems like the smell just constantly comes from the vent. Are there any treatment options or anything you can suggest?

On 2016-09-26 by diana

septic tank is vent on top of septic tank we are getting smell odor in house how to get rid of smell?

On 2016-09-06 by Don

In response to Sarah's problem of sewer gas smell coming from the shower perhaps the water level in the shower trap is low causing sewer gas to escape into the room. This is usually the problem when a drain smells. Solution pour a gallon or two of water down the drain to make sure the trap is full.

On 2016-08-08 by (mod) - improper venting of drain lines or septic tank

Sarah

You certainly need an on-site investigator to help figure this out; by e-text there is just not enough information for me to make a reasonable guess at the problem cause

. If you smell sewer odors keep in mind that besides health worries, such gas can be explosive. You might ask your health department for assistance. Do keep me posted.

On 2016-08-08 by Sarah

I wonder if you can help. I live in a new build property (built 2012).

We live in the country side and share a septic tank with our 5 neighbours on a terrace of 6 houses. The septic tank is at the side of the houses at number 6 property, the only stack vent is in number 1 property. We smell sewerage gases and waste often, especially when it rains or the weather is warm

. I have come home today and it honestly smells as though someone has been muck spreading in my kitchen, even though I had kept all the doors closed (the smell seems to come from the shower drain in the wet room at the back of the house). Please help

, I am wanting to speak to the landlord about this or just ring environmental health... I have 17 month old twin boys and am worried for their health, they were prem babies and have had enough issues without our home causing any more. I hope you have some advice for me. Thank you in advance.

On 2016-08-04 by (mod) - get help from health inspector for trailer park sewer odors

Unfortunately it sounds as if the system is not working properly and could be both unsanitary and unsafe. Ask your local health inspector to take a look; let me know what you're told.

On 2016-08-03 2 by John

An outdoor septic bed in a trailer park located near our trailer site smells horribly bad & we get a smell of "poop" every 5-10 minutes.

We've complained about the issue to management of the park & they've said that everything is running fine with the septic bed however

they are considering to replace the vent lids.
Can anyone give advice or comment in order to possibly stop the smell.

On 2016-07-26 by (mod) - Sprinkler system stinks after it goes off

Anon

No surprise, as often water has resided in pipes, at warm temperatures, for years, possibly supporting the growth of bacteria or algae that may stink.

Flushing the system from time to time or if necessary sanitizing it will stop that problem, but the plumber doing the work must be expert enough to be sure that the sanitizing treatment won't corrode or harm fire equipment such as sensors or sprinkler heads.

On 2016-07-26 by Anonymous

Sprinkler system stinks after it goes off

On 2016-06-19 5 by (mod) - What can happen if you install a vent on septic tank?

you may smell odors close to the vent;

and if the vent is not properly installed and sealed you may permit surface runoff or ground water to leak into the tank, flooding and damaging the system, even causing a sewer backup into the building it serves

and probably something else that doesn 't occur to me immediately

On 2016-06-19 3 by Fred kàlala

What can happen if you install a vent on septic tank?

On 2016-06-10 by (mod) - find the odor source

Pete,

First we need to understand what the odor is and to find its source; check your incoming cold water supply for odors - could be sulphur or iron-loving bacteria in the water source. Those sources are exacerbated in a water heater, even a new one.

Question: rotten egg sulfur smell from septic system while aerator is off

My septic has an aerator and pumps that move water to an above ground sand pit.

The aerator has been off while I wait on a pump float repair. Been a few weeks.When I turn on the pump manually(float broke) I noticed the sulfur smell today.Water never smelled great,but the sulfur is much more intense now.

Can I flush something to lessen the stink,or just run the aerator manually too? I had the aerator off because the back up in water due to broken pump makes the aerator alarm go off.That switch is outside.

This is a newer 2005 singular septic.County required it.Now they require UV light systems.I miss the septics with NO electrical hook ups.Thank you for any suggestions. E.W. 1/1/2014

Reply:

I don't have a full understanding of the design and operation of your septic system, but can offer these general comments:

I would hesitate to add typical chemicals or additives used for sulphur odors to a septic system as you risk killing off bacteria; and it is not normally necessary nor even useful, and in some jurisdictions illegal to use septic system additives or treatments. You might reduce odors by running the aereator manually as you suggest.

If by "singular septic" you are referring to an aerobic system designed and sold by Norweco / Singulair - www.norweco.com then you might contact the company for other suggestions. You can also contact the company at 800-NORWECO, Norwalk Wastewater Equipment Company, Inc. 220 Republic Street Norwalk, Ohio U.S.A. 44857-1196 Phone: (419) 668-4471

Or see our full directory of

AEROBIC SEPTIC SYSTEM ATU SUPPLIERS & MANUALS

It is not a good idea to leave the aerator of an aerobic septic treatment system off for weeks or longer. The risk is not only the discharge of inadequately treated effluent and thus environmental contamination, but possibly system clogging and failiure. I'd want to get that pump going with proper repair parts promptly or if that is not easy, then to ask the manufacturer for suggestions for a substitute pump or part that can be used.

Details about aerobic septic system maintenance, treatments, chemicals and suppliers are

at AEROBIC ATU SEPTIC MAINTENANCE PROCEDURES

Question:

(Sept 14, 2012) jennifer said:

i just moved into a house i am renting, and the smell from the upstairs bathroom when you drain the tube water and the most horrific rotten egg smell comes up too.

i have 5 children and i brought it up to my landlord and she said there is nothing she can do. please help tell me what to do thank you.

Reply:

Jennifer,

If the water supply is not itself smelly then I don't suspect sulphur in the water but instead a sewer gas problem, perhaps due to a blocked drain or improper or inadequate venting. Inadequate or malfunctioning sewer drain venting is unsafe, risking both methane gas leak explosions and potentially gas exposure or pathogen hazards.

I'd ask the landlord, in writing, to address the concern as one of health and safety.

Question: need an air admittance valve (cheater vent or V-200) ?

(Dec 19, 2012) Jim said:

I have a walkout home with a septic system. To get rid of grey water and sewage from the basement there is a lift pump.

When the lift pushes the waste out to the septic system it sucks the water out of the trap at the upstairs bathtub

It doesn't affect the kitchen sink or any other fixtures. I believe that the venting through the roof is probably to small.

I was told by another person that I should install a "Air admittance valve" in my system. Would I install this at the lift in the basement or at the bathtub? If it goes on the line to the bathtub would it go downstream of the trap? Thanks for any help! Jim

(Feb 9, 2013) joe said:

hello i have an overactive sewer smell coming from the roof vent on the roof; not all the time. it's an in-ground septic system. will extending the vent a couple of feet higher help? thanks

9/19/2014 Brent said:

I live in a home that is on pier & beam foundation. Recently we had a sewer line break that we were unaware of for about a week. It was repaired but naturally very damp. I put a strong fan under the house to dry out the soil.

It has been about a week and we re now getting a smell in the house naturally the reeks of dried sewage. What can I do to rid of the smell?
Thanks

Reply:

Brent

Unfortunately you'll need to remove contaminated soil, possibly treat what remains with a sanitizer or disinfectant, and you may need to add a plastic ground cover as well.

Comment-Opinion: recommends filters atop plumbing vents

(Mar 7, 2013) Rod Pennington said:

The well known rain storm term "it was a gully washer" comes from the fact that sewer vent pipes all used to exist at ground level by design. Because of odors the "gully vent" was moved to the roof in the US and worldwide almost a century ago.

Moving them to the roof allowed the wind to dissapate some of the smell, but they still stink, now refered to using a newer plumbing term "stink to high heaven."

The only way to "Stop the Stink," is by using a vent stack filter. Initially these filters were simple activated carbon, but because activated carbon allows a pugging type of slime growth newer carbons such as Zeocarbon and Chemically treated carbon to prevent growth are now more effective

Reply:

Thanks for the comment Rod. Odor Hog in Tucson offers such vents as do other companies.

Watch out: adding filters atop a plumbing vent may risk vent clogging and thus poor drain performance or sewer gas entry into a building.

Question: sewer line break under home on piers

(Sept 18, 2014) Brent said:

I live in a home that is on pier & beam foundation. Recently we had a sewer line break that we were unaware of for about a week

. It was repaired but naturally very damp. I put a strong fan under the house to dry out the soil. It has been about a week and we re now getting a smell in the house naturally the reeks of dried sewage. What can I do to rid of the smell?
Thanks

Reply:

Brent

Unfortunately you'll need to remove contaminated soil, possibly treat what remains with a sanitizer or disinfectant, and you may need to add a plastic ground cover as well.

Question: sewer gas from sink drains and shower floor drain

(Oct 13, 2014) Michael Wood said:

We have lived in our home for 30 years and never had a septic problem. Now, in only one bathroom, located farthest from the septic tank, we get sewer gas coming up through the drains of both sinks and the floor drain in the shower. Of course the whole system is vented with a 4 inch vent pipe which is located at about the midpoint of the drain system

Is it possible that there is actually gas pressure building up in the drain pipe and some how bubbling back through the sink and shower water traps? Any other ideas as to how to fix this annoying problem. Thank you so much for your advice.

Reply:

Gas pressure in the plumbing vent system would normally vent through your drain-waste-vent piping above the building roof; but that system could be leaky or clogged.

Question: septic tank smells

(Oct 16, 2014) Danny Miller said:

My Church has two septic tanks, 1,500 each. One is 19 years, the other is 9 years. The 19 was cleaned out when the second was installed.
The two are putting out a Lot of smell, some I had a cleaning service come out, and check. The older one only had about 6in., of solid in the bottom, with a lot of flowing, the smell, when it was Opened was more then one could stand !

It's was not pump out, do to the lack of Solids !

The newer one was opened, the smell coming out of it, too was just has bad as the other. It had about 12in., of solid in it so it was pumped out !

The smell is what is my concern, one goes out side, and the smell is there, is there a lack of water going thru the tanks ? There are NO washers of any kind, and the only people there is on Sunday, of any real number. We are a Small Church, of only 80 to 100 people in early service, and 30 in second !

The rest of the week little to No one there !
There are no Bath, or Showers, being given, or taken. Were on City Water so there's no water solfner back flushing.

Reply:

First please review the list of septic system odor diagnosis and cure suggestions in the article above. Let me know if any of that is unclear of if you are still left with questions.

It is normal for an open septic tank to smell. If the septic tank cover is not properly secured it may be both smelly and fatally dangerous (if someone falls in) so start by checking the septic tank covers and access ports for signs of leaks out (odors or sewage) and leaks into the septic tanks (flooding and drainfield failure or line blockage).

Question: acetone odors in cold well water

(Oct 17, 2014) KAREN VAN ESSA said:

For the first time in 10 years I can smell acetone intermittently in my cold water, which comes from a drilled well 130 feet deep. I have had the water tested for a broad range of chemicals at least twice before: levels were below all guidelines, except for sulphur and hardness, but the levels are tolerable and I have no water softener.

There has been no construction in my rural neighbourhood, the nearest house is 500 feet away, and the only industrial site is a car wreckers/body shop about 1/2 a mile away whose owner is semi-retired.The land has not been farmed for at least 25 years. What could be the source of this volatile? Could it be natural? (this is a mainly wooded area with small streams and ponds)

Reply:

Karen

Acetone would not be associated with a septic system failure or odor problem - the topic of this page.

You will want to see CHEMICAL ODOR SOURCES where we'll re-post your question and our reply.

Question: gas smells through toilet pan

10 Nov 2014 Don said:

We have 3 toilets in our house and are constantly getting gas smells which seems to even be coming through the toilet pan itself.On inspection, the plumbing is always spotless and the vent pipe is clear

.The smell is such that if a match was lit it would blow the establishment to blazes!!It doesn't seem logical that the smell would come through the water trap in the toilet pan,but that seems to be the case. I have even lifted the lid slightly on the tank and there the smell is nothing more than you would expect. Any sugestions would be welcome.

Reply:

Don

I'm not sure what is meant by "toilet pan" but if you mean the bowl or base of the toilet, the problem could be faulty wax ring seals. I'd pull the most-offensive toilet and then inspect and replace the wax ring seal.

See LEAKY TOILET SEALS, ODORS - for repair procedure suggestions

Question: trace toilet odors to leaky seals

(Nov 10, 2014) Don said:
We have 3 toilets in our house and are constantly getting gas smells which seems to even be coming through the toilet pan itself.

On inspection, the plumbing is always spotless and the vent pipe is clear.The smell is such that if a match was lit it would blow the establishment to blazes!!It doesn't seem logical that the smell would come through the water trap in the toilet pan,but that seems to be the case.

I have even lifted the lid slightly on the tank and there the smell is nothing more than you would expect. Any sugestions would be welcome.

Reply:

Don

I'm not sure what is meant by "toilet pan" but if you mean the bowl or base of the toilet, the problem could be faulty wax ring seals. I'd pull the most-offensive toilet and then inspect and replace the wax ring seal.

See LEAKY TOILET SEALS, ODORS - at inspectapedia.com/plumbing/Toilet_Seals.htm

Question: rotten egg odor from toilets

(Jan 4, 2015) Bill said:
Several times year we have a rotten egg smell coming from our toilet closest to our septic system. It lasts 2-3 days and goes away for months. What would you suggest we do to see why this is happening.

Reply:

Bill look for a loose or damaged toilet wax ring seal

Question: cracked cast iron waste pipe repaired, odors persist

(Feb 20, 2015) Betty said:
One lengthy waste water pipe (cast iron) was cracked and replaced, but the septic odor continued
to appear after doing laundry. Odor is in basement, plus on occasion in the laundry room itself.
Plumbers want to replace the remaining waste water pipes and install a new flange in downstairs toilet.
Any comments?

Reply:

Betty,

Do you think the odor is from incomplete sewage cleanup?

If not then I'd look for a plumbing vent or floor drain problem.

Question: Odors make our patio unusable

(Mar 3, 2015) Jim Renfree said:
I have a 1200 gallon dual compartment concrete septic tank installed in 2011. There are sanitees at both the inlet and outlet to the tank. We are very careful using only septic approved toilet paper and cleaner (simple green), and do not use a garbage disposer, (tight fitting screens on kitchen sink drains).

We still have septic odors coming out of the roof plumbing vents even though we used Rid-X septic starter a few times.

The odor, especially when water is running, makes our patio not very usable. Does the dual compartment provide sufficient baffle against floating scum that we could cap off the top of the inlet T to prevent gasses from escaping back up the inlet line? (ie, is the outlet T sufficient to vent the gasses?

If not advisable, I could put charcoal filters on all roof vents I guess, but is there any concern that my tank is not operating correctly?

Reply:

Jim Sanders said:
If you smell sewer gas, it's important to fix it as soon as possible. It's not only very unpleasant, but can be dangerous. Thanks for the great article!

Editor: Jim, septic additives and treatments are not generally necessary, can be harmful, and are prohibited in some jurisdictions.

I'd look at wind directed caps on plumbing vents, higher vents, and I'd look into the septic system for signs of backps at the tank or D-box.

Question: septic mound system vents

(Apr 4, 2015) John said:
The home we wish to purchase has a mound system and the vent is right outside of the back of the house, about 20 feet from the house (and, more importantly its windows). It sticks up about 3 feet from the ground. The owner has the vent capped saying that occasionally there were odors.

He said he has the top of the vent if we wish to reinstall it, it’s just a matter of placing it back on.

We cannot find anything online about the vent for this system and if they function well with it capped.

He’s going to have it inspected but we’re afraid that he could put the vent on for the inspection then recap and the system won’t work properly for us.
Can you shed some light on this or point us in the right direction for obtaining this information?

Reply:

John

The vent you describe assists in avoiding sewer gas backup into the home and depending on piping routing it might also be assisting in movement of sewage or effluent through the piping system similarly to the role of vent piping in a building's drain-waste-vent system. If the designer of the septic system included a vent it seems to me we ought to keep the vent working.

The cost of putting on or taking off the cap, itself, is trivial.

Whether or not the fooling around you describe is an effort to mask a problem I can't say, but it's possible that there were complaints of sewage gas odors.

Question: pungent smell from toilets, worse at night

(Sept 10, 2015) Marisa said:
We have just recently moved to a house with 2 toilets.there is a very strong and permenent smell coming from both toilets and the smell gets worse at nite and the toilet doors are close.immediately u open the door the stench is so strong.

i have tried smell the every corner of the toilet and on closer inspection i noticed that both toilet pots were shaking slightly when u sit on them meaning they havent been properly fixed to the floor.

could this be where the stench is coming from?and what can be done to get rid of the stench.its unbearable.

Reply:

Sounds as if most likely the toilet wax ring seals that seal the toilet base to the waste pipe are defective, squashed, missing, or improperly installed. If so, the toilets need to be removed and new wax rings installed.

Question: sewer gas smell after doing laundry

(Oct 5, 2015) John said:
We have two bathrooms one up stairs and one on the main level, the bathroom on the main level has sewer gas smell after running water from other areas laundry on main level, tub and or toilet on the upper level.

We recently had the 2nd tank in our system replaced, I opened the first tank access port tonight and the water level is about 1/2 inch above bottom of the inlet pipe. Should there be an air space between the inlet pipe and water lev

Reply:

Check for sewer odors from floor drains and check for a laundry drain that's not vented outside, or whose trap is not maintaining its water seal.

Question: smells from a nearby hotel sewer

(Oct 14, 2015) Theo said:
There is a hotel whenever the wind blows in a certain direction it starts smelling in the building they have 2 manholes on that line as well as 2 air vents coming out to just above ground level which are close to the building what can the cause be and is there a way to rectify this

Reply:

Theo,

As (depending on where else sewer gases are backing up) there could be explosive methane gas hazards this is a question for your health department and local safety officials.

Question: septic tank too close to house, stinks.

(Oct 21, 2015) Anonymous said:
My septic tank is approx 2metres away from the front door, is this too close. Also do all septic tanks have leach fields, does this mean my garden is the leach field. There is always a contestant smell coming from the garden and the toilet.

Reply:

All septic tanks use some sort of effluent absorption system, soakaway bed, drainfield, leachfield, soak pit; otherwise you'd have a holding tank that you'd have to pump rather frequently and that's usually not permitted. Your tank may be backing up due to a field failure.

I can't comment about your garden as I don't know if it's on the septic fields (perhaps unsanitary and unsafe) or not.

Question: can a septic tank lift up out of the ground

(Nov 27, 2015) trish said:
Will a septic tank lift?

Reply:

Possibly if there are frost heaves or alternatively uneven settlement could tip a septic tank making it appear to "lift" at one end or side. Plastic or fiberglass septic tanks, if empty, will float up out of the ground during area flooding. Search InspectApedia for FLOATING UP OIL TANKS to see a similar case.

Question:

(Nov 29, 2015) Emma Robson said:
My waste water pipe is emitting offensive odor;what can I do to stop it.

Reply:

Emma the articles in this series including the page above suggest where to look to find the source of the smell - then we will know what repair is needed.

Question: odors from roughed-in bath?

(Jan 16, 2016) Angela said:
We have a bathroom roughed in the basement. Nothing is hooked up to it yet. The furnace is draining into the sewage tank. We pumped it out but it still smells. This is a new construction a year ago. Didn't do this last winter

Reply:

Angela,

It would be no surprise for an in completely installed bathroom to suffer sewer orders from its connection to inactive septic tank as you are missing either plugs or water traps where the fixtures belong.

What on earth is a "furnace" draining, and why would it be draining to a septic tank? This makes no sense to me - together we must be missing something, or you had a very creative builder.

Question:

(Jan 25, 2016) Tim said:
My 1950's ranch had a new 3bedroom septic system installed before I bought the house in January of 2015. With that said, we did a full bathroom remodel and new heating system and changed the old cast iron vent stack to PVC and most of the plumbing was replaced at that time as well.

Well there are only two of us in the house. The septic odor outside is extremely bad at times. I bought a filter to go over the stack, but when I put it on, for some reason the septic smell appeared inside my house.

I do have a "slop" sink in the basement as well as washer/dryer. These are all pumped out to the septic tank when in use.

Not sure if somehow that pump is causing some issues to the ventilation of the system? All that I do know is the smell is horrible!! I need to fix it asap. Anyone have any suggestions?? Thanks in advance!

Reply:

I'm lost. Perhaps an onsite expert can sort this one out.

Question: bad septic smell when kids take a bath

(Jan 27, 2016) Mike said:
When my kids take a bath, I get a bad septic smell outside the house. I have a two tank system (brown and gray water), and just had them cleaned out about two months ago. I also recently noticed that two sinks on the second floor gurgle when using them. Could that add to the problem?
Any suggestions?
Thanks!

(Apr 8, 2016) Lu said:
I have the same problem as mike, would love to hear some suggestions. Had the septic tank cleaned out last year. Before that was 7 years

Reply:

Look for a blocked main drain or defective venting that causes sink traps to lose their water seal.

MIke and Lu:

Unfortunately, cleaning a septic tank will not fix odor sources such as a septic tank leak, piping leak, or worse, backing up into the septic tank or sewer system from a flooded drainfield.

I'd start by inspecting the tank sewage levels: if the tank wastewater level is over the bottom surface of the tank outlet pipe then there is a blockage or flooding problem from that point outwards. Next check the D-box for flooding or signs of a blocked drainfield line.

Question: Rain leads to flooded yard and septic smells

(Mar 31, 2016) Doug said:
Everytime it rains hard my house smells from the septic and water lays all across my yard. How can this be fixed?

Reply:

Doug:

I suspect that your drainfield or soakbed is fully saturated, maybe even under-water, and that the result is that effluent, mixed with rainwater, is probably back-flowing into the septic tank.

WATCH OUT: the risk is a sewage backup in the home. Run as little water as possible until things quiet down.

Check also for water leaking directly into the septic tank.

Ultimately if this problem is frequent and it's drainfield saturation you'll need to either get groundwater away from the septic fields or re-design the drainfield to a higher mound or raised bed type system.

The first option - routing surface runoff away, is the least costly but for that to work you'll need to be convinced that it's really *surface* runoff and not groundwater (under the ground surface)

If site location and shape permit, digging an intercept drain that catches water running towards the drainfield and drains it away to a safe location can work.

...

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Recommended Articles

• SEPTIC SYSTEM ODOR CURES
• SEPTIC / SEWER ODOR SOURCE TABLE
• SEWER GAS ODORS - home
• ODOR CONTROL for SEPTIC TANKS
• ODORS GASES SMELLS, DIAGNOSIS & CURE - home

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