Sewer Gas Smell
DEAR TIM: My daughter's house has a chronic sewer gas odor problem. The odor is strong when it rains and the furnace or air conditioner is operating. The odor gets so bad my daughter and her family evacuate the house. Three plumbers have not been able to solve the problem and we have checked all plumbing fixture traps, caulked where the basement floor meets the foundation, etc. My daughter is ready to sell the house for a loss. Can you help? Dave S., Shelby Township., MI
DEAR DAVE: Sewer gas can be a vexing problem to solve, but it is by no means impossible. As much as I hate to say it, the three plumbers that were consulted are either inexperienced or they do not keep up with technology. The good news is I doubt your daughter has to move and take a loss. It is my guess the source of the odor can be found and repaired for less than what a moving company would charge just to move your daughter and her family.
The water seal in this toilet is broken. The water level has dropped below the back lip of the trap and sewer gas was entering the room as I took the photo. PHOTO BY: Tim Carter
Sewer gas is created by the decomposition of waste materials that are found in public and private sewer systems and private septic systems. The characteristic odor can be overpowering and it is toxic. To add further insult to injury, the gas is explosive as it often has a methane component.
Plumbing drainage systems are designed to keep this sewer gas inside the pipes and any that does exit to the atmosphere happens outside the home through the vent pipes that poke up through the roofs of houses. These vent pipes on the roof are actually intake vents, not exhaust vents as most people believe. When a large volume of water enters a plumbing drain pipe it pushes air in front of it towards the sewer or septic tank. This air must be replaced and it is sucked into the plumbing system through the roof vents.
The source of the sewer gas can be plumbing fixtures whose traps have gone dry or have lost enough water that the water seal within the trap has broken. You would be surprised to discover that water can rapidly evaporate from toilets and the traps below tubs, floor drains and just about any fixture within a few months. In fact when my daughter is away at college I have to flush the toilet in her bathroom every three weeks to keep the bowl filled with water. If I don't keep the toilet seat down, I have to flush the toilet weekly as some household pets seem to love to drink water from clean toilet bowls.
Cracks in either plumbing drain lines or vents pipes are the other source of sewer gas leaks. If the crack is in a drain line, you often see an associated water leak. But vent pipe cracks are far more elusive. They can leak vast amounts of sewer gas and you might not be able to locate the source easily without a special machine. The furnace and air conditioner clue tells me the leak might be in a vent pipe that is close to a return air duct. The leaking sewer gas is being sucked into the return air system and then broadcast throughout the entire house by the air handler in the furnace.
Sewer gas leaks can be quickly discovered by a plumber who owns a very cool machine that generates artificial smoke. The smoke is simply visual and does not create a lasting odor nor does it stain any surfaces in a house. The plumber connects the smoke generation machine to the plumbing drain system and then blocks off the drain pipe leading to the sewer and caps off all roof vent pipes.
Once the smoke machine starts, it begins to slightly pressurize the plumbing system. If there is a cracked pipe or a fitting joint that is loose, the smoke readily exits at that point before it would bubble up through a fixture trap filled with water. Usually the source of the sewer gas leak can be discovered in less than one hour.
Sewer gas problems can also be caused by plumbing vent pipes that are clogged. This can happen in old homes where a cast iron vent pipe gets clogged by years of rust scale that falls off the inside of the pipe and clogs a 90 degree bend in the pipe.
Tennis balls, leaves, and all sorts of other debris can clog plumbing vent pipes. When a vent pipe is clogged, the replacement air needed by the system will get sucked into the pipes through a fixture inside the house. When a large amount of water is placed into the drain pipes by a toilet or a powerful washing machine pump, it can readily suck the water out of a nearby bath tub trap or even a kitchen sink trap. Once this happens, sewer gas immediately enters the room through the dry fixture trap.
To slow evaporation from fixture traps that are not used on a frequent basis, fill them with water and then slowly pour four ounces of mineral oil into the fixture or floor drain. This mineral oil will evaporate far more slowly than water and the trap will remain wet for many months.
Author's Notes:
I received these emails after my column was printed.
"Tim:
In regard to the sewer odor problem in Shelby township Michigan: If they have a sump pump in the basement and have a french drain around the perimeter of the house, there could very easily be a broken sewer pipe right outside the basement wall. When it rains, tainted water gets in the drain, goes to the sump, odor is in basement, return air to the furnace distributes odor throughout house.
Enjoy your column in the Telegraph Herald."
Dave B., Dyersville
"Hi Tim:
My name is Gary Whiteman of Whiteman Land Service, Curtice, OH. We do pond construction and new home site development.
I read your article in the Toledo Blade, Dec. 18 and noticed that there was no mention of possible sewer gas from homes that have a leach field system. We have had many people complain of sewer gases from their basements. We have found that the cause was due to other contractors who did not remove previous farm drainage tile from under the leach field area and to the home foundation or basement.
Thus, the waste water travels through the farm tile under the leach bed to the drainage tile around the footer and into the sump crock inside the basement. To solve this would be to remove the farm tile between the leachfield and home.
Contractors excavating for the basement or foundation, and also the leach field, should remove these tiles at least twenty-five to thirty feet away from the home area. I hope this info will be helpful.
Regards,"
Gary
"Dear Tim,
We had a perplexing sewer gas odor in our home. After spending over $3,000 in fees with plumbers, locators and other experts, we still had no answer.
Finally a very knowledgeable plumber discovered an illegal connection in our drain system. The person who installed the condensate drain line from our air conditioner installed it without a vent line. Each time our washing machine would pump water into the drain system, the rush of water would siphon out the water in the small trap of the condensate line.
The sewer gas from the main sewer line would then travel up through the condensate line and into the actual air conditioning air handler. When the air conditioner would run, the moving air would suck vast amounts of sewer gas into the ducts and broadcast it through all of the air vents in our home.
Once the condensate line was disconnected from the drain line and piped directly outdoors, our sewer odor disappeared immediately."
Sandra Farmer, Paradise Valley, AZ
Hi,
4 years ago we had a new septic field put in, the tank was not replaced, 3 business advised the tank was fine. We have noticed a terrible septic gas smell outside of our home. Water drains fine, no back ups and no smell inside the house, just outside. So who do I call? Do I call a plumber or septic company?
Thank you
Jamie
I have read the problems about sewer gas and have a unique situation. We moved into a new home and when we leave the doors open to the back screened in porch we get what smells like a sewer gas odor in the house. there is a sewer pump station within about 50 yards behind the home but the is downwind of the house. I sit on the back porch frequently at different hours of the day and there never seems to be a smell outside. The smell is only inside after the doors have been opened for awhile. Research to date has been for naught.
Any suggestions would be appreciated
Richard,
Lots to discuss. This is why I have my 15-Minute Phone Call.
An sewage odor occurs in the bathroom faucet after I flush the toilet. Can you tell me what the problem is?
Angela,
Clogged vent pipe or inferior plumbing installed.
To talk about it, consider my 15-Minute Phone Call.
I live in a Condo and called the association to report the sewer gas in by unit. All they did was to tell me to call a plumber. I am retaired and can not spend a lot of money on a plumber. It has been almost two weeks now and it effects my eyes.
What should I do? I live in Aurora, Colorado, at Foxdale.
Carolyn
Carolyn,
Talking with me for 15 minutes may be far cheaper than calling a plumber.
Hello;
I had a sewer smell in bath tub until I had trap replaced. now I have sewer smell in wall where vent pipes are located. The smell only comes when the temperature outside in 85 degrees or greater.
Bob, you need to schedule a 15-Minute call with me.
We have noticed a septic smell from our septic system had it pumped out still from time to time we would smell it outdoors, have added enzymes for the bacteria, still have the problem not all the time, found a place in the yard where the smell is on the ground but the ground is not soggy. The only drain we have an issue with is the washing machine will back up into the kitchen sink when it spins out, but it drains on down. Really need help on this.
Thank you
Dena
Dena, your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!
When I run my washer, sewer gases come up from the bathroom, so I guess the traps are running dry? how easy and expensive is this fix?
Kim, your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!
I am a new City Maintenance personnel. I have inherited a problem with one of our buildings that has a sewer gas smell ONLY when there is a northwest wind. It is a flat roof building that slopes from east to west, shares walls with two other buildings and it is actually shorter than both adjacent buildings by about 10 feet on the north side and about 30 feet on the side south. The sewer piping is new with no cracks. The vent pipe has a frost-free cap which is about 2 feet from the top of the roof. The closest shared wall to the pipe rises about 2 feet above the pipe about 8 foot away to the south.
David, your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!
The toilet in the master bedroom appears to not have been flushed when we return home from work and has a strong odor. It looks as if the sewer is backing up but the plumber could not find any blockage. Any ideas?
Lynn, your question require lots of typing and I have some questions for you. You should consider investing in a 15-Minute Consult with me. Look at my cart for that. Lot's to discuss. I just do short pithy answers here.
I also have a sewer gas smell, have investigated the p-traps, poured bleach, it does seem to be when the blower kicks in on the furnace so I'm thinking it's the vent pipe. I also have arranged to have my septic tank pumped just in case that is too full and not working properly. Any other thoughts?
Traci, your question(s) require lots of typing and I have some questions for you. You should consider investing in a 15-Minute Consult with me. Look at my cart for that. Lot's to discuss. I just do short pithy answers here.
Our home is built on a slab. We are experiencing heavy sewer gas odors. We have had two plumbers check it. The first one replaced a drain the second one repaired a toilet seal. The odor is still very bad . It is worse in cold weather. What else do you recommend ?
Linda, you need to do a 15-Minute Consult with me. Look at my cart for that. Lot's to discuss. I just do short pithy answers here.
My problem is sewer gas outside my home. We have city hookup. My general contractor did his own plumbing? Anyway when it was time to hook up to the city sewer line he discovered that one of the supports for my deck was directly in the way. Instead of a nice straight outlet from our house it's crooked and I'm thinking that it does not drain our home correctly. I think that this creates an usually strong oder from a slow moving system. So I think a lot of gas is coming of the roof? Any comments.
David, I have questions. This is really a consult that can't be done with a two-sentence reply. You can talk with me for 15 minutes.
Hello,
My family and I live in a 1949 Cape Cod style home that has a horrible sewer gas issue. Not every time but when you flush our toilet upstairs the sink and tub gurgle and then put out sewer gas smells. We have had a local company come to our home. They checked all the traps in tub, sinks, basement, and also checked the roof vent and outside municipal tank. The cleaned the traps and checked the flow into the tank outside. They were at a loss to what was exactly the problem. The man told me it could be that the house isn't properly vented or that the older pipes could need to be replaced. We have no clue and I would like to have an idea of what it might be so we can try to remedy this.
Jennifer, Walter, this is what my 500-Second Consult is all about. Click the Shop icon at the top of the page!
We have a suspected sewer smell, however none of the P traps are dry. From the sink the waste pipe flows almost horizontal to the right and then vertically straight down through a spare room one floor underneath, then into the floor of the spare room and turning horizontal and exiting with the rest of the plumbing. We have had the waste pipe inspected with a camera and a smoke machine. There are no visible defects. There is no ventilation for this waste pipe. However each plumber who looked said that there should be a vent, but if it was a ventilation problem the smell should be coming from the sink upstairs through the trap. Is it possible for the smell to seep through the PVC pipe and into the room? This pipe is waterproof and the smoke machine found no leaks. It's a bit perplexing. The smell is only noticeable when the window and door are closed for more than 2 days.