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Due to the tremendous amount of feedback we’ve received on this section of the site we’ve decided to start another article showing some of the basement odor questions we get get via email. We’ve attempted to problem solve as best we can over the internet. Here is a request, from us, if you have an issue that can be clarified with a few pictures send those over with an email. I will ask for your permission to post the questions and answers before publishing. Thanks Keith and Al for the questions.
Keith : “I just have a question. What would be the cause of sanitary waste dumping into a sump pump pit that is only used for removing ground water? My house doesn’t have a sewage ejector. The sanitary waste piping connects directly to the town sanitary system. Also, the sanitary waste is dumping into the pit on dry or raining days.”
TPI : First of all thanks for contacting us. I’d be glad to help. I have a few questions for you before I give you an answer.
1) Are you sure no other plumbing fixtures dump into that pit? i.e. laundry tub, shower drain, basement bath etc.?
2) if no other plumbing fixtures are draining into the sump pit then you most likely have a sewer line break somewhere. Just because everything is draining properly does not mean you don’t have a break.
3) to determine whether or not a sewer line break is the problem, you need to do some dye testing. You can call in a professional plumber or you can look for some plumbing trace dye on-line. The most popular trace dye colors for plumbing are florescent yellow/green or blue. You can use food coloring but it usually dilutes too quickly to be very affective. So you’ve got the dye so what do you do with it? Fill up a bathtub and put some dye powder or tablets in the water, put a couple tablets in your toilets then proceed to drain and flush away. Continue to run water, if you have a waste line break the dye will eventually make it’s way back to your sump pit. It may take an hour or so but it will show up.
Hope this helps.
Keith : “Thank you TPI for your reply. Nothing else drains into the sump pit. It is strictly used for ground water (drain tiles) in the basement. I will try the dye, but I feel it will be an expensive job. I was told last year that our main sewer (front lawn) is clay tile and tree roots are growing through it. So to replace it won’t be cheap.”
TPI : The dye testing won’t be expensive. If you can wait a few days I can drop some tablets in the mail for you and you can do it yourself. Just have someone downstairs with a flashlight checking the water coming in the pit. The sewer repair can fluctuate wildly depending on where you live. You can find a dependable contractor to do your project for 3K to 4K. For a union contractor that price is a little low. Again depending on where you live you might be able to find some out of work plumbers willing to work for ** to ** bucks per hour. Gosh knows there are plenty where I’m from. Let me know if I can help you in any way. See ya.
Keith : “Thanks again, TPI. I didn’t mean the dye test would be expensive. I meant repairing/replacing the sewer pipe would. I am going to have a plumber snake the sewer pipe, hopefully that will take care of the problem (temporarily).
Yes, the tablets would be fine. What is the cost?” (We are providing those dye tabs free of charge)
Most likely this is a house sewer main that is cracked by settling of tree roots. The waste water is seeping into the soil and making it’s way back to the sump pit, hence the smell.
Here is another email we received:
Al : “Recently moved into a 20 yr old home with a septic system. When running the central AC, an overpowering septic smell builds up in the basement. The furnace blower runs on the highest setting when the AC is on and seems to create negative pressure in the basement which then seems to pull in the septic gas. The house was vacant 1 yr prior to our move-in. Have checked all the traps and floor drains: wet & no smell. Confirmed the stink pipe is clear by running garden hose water down in. Also cleaned the AC coils, trap & drain lines, and have eliminated bacteria, animals, mold, etc. in the HVAC as the problem. There is no smell unless the HVAC blower is running on HI. The smell appears to originate in the horizontal run of the septic vent pipe in the basement joists. Does not appear to be coming from the ejector pit although planning to replace the seal as part of the process. Changing the AC blower from Hi to Med and providing additional air paths to the basement have temporarily allowed operation of the AC.
Please advise best method to track the source/solve the problem from here.
Is smoke testing a good method?
Am new to owning a septic system and my ignorance is profound and deep. Any help greatly appreciated.”
Al
TPI : Hey Al I’m glad you found us. You’ve done quite a bit of the trouble shooting yourself, am I too vain to thing that you followed our trouble shooting guide? I think you have a break somewhere on the run of vent piping and a smoke test works well. I would start out with a peppermint test first. Smoke can be messy. Have you had your septic system pumped out/cleaned? Let me know.
Al : “Thank you for the quick reply.
Just found your site this morning. All trouble-shooting done by yours truly to-date came from web searching and talking to plumbers. Wish I had found your site sooner.” (We know this is a shameless plug but he wrote it so we’re publishing it. Thanks Al).
“Septic system was pumped in April by the previous owner as a condition of the sale. I also talked to the individual that performed the pre-sale inspection (external system only) and he did not find anything awry during his inspection”
“What is a peppermint test?”
A new wrinkle as of today: I have boosted the HVAC blower back-up to HI and turned on the AC. After 1.5 hours of running, no smell. Not sure to be relieved or greatly frustrated.”
TPI : A peppermint test is used to determine breaks in vent piping much like a smoke test would. Go to the local grocery store pick up a bottle of the “Oil of Peppermint”. Go on top of the roof (be Careful) and drop several drops down your vent line. Be careful not get a whiff of the peppermint it messes up your sense of smell. You can go down stairs and see if you smell the peppermint. If you do you know you have a vent break.
Al : “Relative to having no smell today, I did pour water down the garage floor drains yesterday. The house had been vacant for a year prior to our move-in and the garage drain traps were probably dry. Puzzled that this could be the source but the original builder listed this as one item to check.
“We have run the AC on full blower speed a number of times today and no smell yet.”
“Fingers are crossed to point of being painful”
Thanks again guys and thanks to all of our readers for the great response.
Admin
Hi, This is really Good and provide me answers to all my questions about musty basement odor. This is really informative and I will for sure refer my friends the same. Thanks.
I’m glad that I found your site and I am taking in all that you have written on here. I have a bit more unique situation in my basement.
We have a walkout basement and no sump or sewage ejector pit (we’re on a slope which is why I assume we have neither of these). We’ve in the past had your every day ‘belches’ from the tank when too much water goes through (too many loads of laundry or the like). My next door neighbor had some work done on our common tile and ever since, our basement has stunk. We had the tank pumped and the septic guy didnt find anything wrong with our system (it’s a Nyadic) and it was flowing properly. We’ve put the necessary chlorine in the tube and everything outside.
We have a rough in for a bathroom with 2 PVC pipes just sticking out of the basement floor which were duck taped shut when we bought the house, we eventually put caps on them. We also have a drain for the furnace. We have poured water down both pipes and the drain and it seems to be coming from one of the pipes in the rough in in particular. I have duck taped the caps to try to stop the smell from coming up. Any suggestions as to the smell?
Your reply is coming.
Sean
I also want to add that we have checked the vent pipes up on the top of the house and ran the hose in them checked the septic tank and the bathrooms and everything is draining fine. We re-hosed the pipes in the rough in and the furnace drain too.
I was rereading you posts (sorry I know that your response is coming, but I think we found the problem). I used my nose and found another drain in the basement, actually I think that it’s for the toilet. We’ve poured water down there but it’s still smelling. what can we use to cap it off? it’s literally just a hole in the basement floor, pipe flush to the ground so a typical ‘cap’ wont work. If it’s not that then I’ll be back on here, but that’s definitely where the smell is coming from (it’s about a foot behind the pipe that I thought that smell was coming from).
Hey Beth I’m glad you think you’ve found the source of your problem. You can do one of two things.
1) Buy an Econo Plug. An Econo plug is a rubber gasket sandwiched together between two metal plates held together by bolt topped by a wing nut. You place the econo plug in the drain pipe and tighten the wing nut. The rubber gasket inside smashes together and expands to seal off the pipe. The wing nut will sit slightly above the floor.
2) If you have no intention of using this opening for awhile take newspaper or a burlap bag, stuff it in the piping and pour a layer of cement over the paper/burlap. If you need to use the drain line you take a hammer, break up the concrete and pull out the paper/burlap.
Sean
theplumbinginfo.com
Great site and very informative.
Here are the specifics of my situation:
1. Ten year old home.
2. Ejector pit in basement. Pit is vented and the lid is bolted and sealed. Items draining directly into the pit are: toilet, shower, washing machine and floor drain.
3. The floor drain is connected to the ejector pit and is located approximately three feet from the pit. Discharging into this drain are a water softener and condensate from a boiler. The discharge tubes end below the floor grade but above the seal (I rely on the discharge from the softener to create the seal in the trap).
4. At the far end of the room (approximately eight feet from the drain) is a Munchkin boiler. The boiler is used for hot water heat and household hot water.
5. The boiler’s air intake is piped to the outside of the house.
Here’s my problem; when I use my wood burning fireplace I have a terrible sewage smell coming from the boiler. I can burn all day long and not have any odor but almost immediately after the boiler kicks in, the odor begins. The boiler, floor drain and ejector pit are all located in the same room but I cannot detect the odor coming from anything but the boiler. The odor is quite profound.
Thanks in advance for your help!
Gary
Hello Gary thanks for the question. Let me see if I can help. The first thing is you most definitely have a negative pressure issue when you use the fireplace. The air is moving, the hot air is rising and it’s pulling the sewer gas in from somewhere. I know you feel as if it’s coming from the boiler or the floor drain close by and that maybe true but it may be a cracked vent somewhere and that’s where I would start. Have a plumbing contractor do a smoke test on the vent system this will tell you right away of there is a breach in the vent system and it eliminates some things right away. It is certainly possible that the negative pressure is blowing out the trap and you are getting sewer gas from the ejector pit coming up through the floor drain and into the boiler. Try that first and if you need more help give me a shout.
admin@theplumbinginfo
Thanks, I appreciate your response and suggestions.
The part that still has me puzzled is that I can use the fireplace and not detect any odors but as soon as I turn the boiler on the odor becomes obvious within a few minutes.