InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Sewer gas leak sources, sewer or septic gases through conduit or ducts:
This article describes the detection and repair for sewer or septic gases & smells that are traced to passage through electrical conduit, open piping, or HVAC duct systems. We describe how odors may be traced back to electrical wiring, conduits, or panels & sub panels, and how people stop that odor passage.
Septic & Sewer Gases & Odors from Electrical Conduit, Open Pipes or Similar Passages
Reader Question: How do I Seal a Septic Gas Leak Entering the House Through Electrical Conduit?
Question: Does InspectAPedia.com contain a section on how to properly seal conduit used for septic tanks and pumps?
The [InspectAPedia.com] web site is fantastic! There’s a ton of info on septic systems and septic odors.
I have a septic tank and pump station (sewage leaves house and goes into original septic tank, then goes to a second tank with filter, and then goes to a pump, which pumps to leach field). The pump station has a vent (which does not appear to be clogged).
I clean the [septic] filter a few times a year (the plastic type that you pull out, rinse off, and re-install). The pump station conduit runs into my house. I’m assuming the conduit from pump station to the house must not be properly vapor sealed as I get sewer odor at electrical junction box (it took me quite a while to figure out where the odor was coming from).
The [septic] odor very consistently tracks to the filter cleaning cycle. Immediately after cleaning the filter there is no odor for the first few months, and then eventually the odor becomes noticeable and continues to become stronger and stronger until I clean the filter ... after which the odor goes away for another few months and the cycle repeats.
I’m not certain I fully understand why this occurs, but the cycle is consistent. The plus side is I always know when the septic tank filter needs to be cleaned. However in addition to the unpleasant odor that I smell when it’s time to clean the filter, I’m concerned about having septic gases in the electrical conduit.
Does the web site contain a section on how to properly seal conduit used for septic tanks and pumps?
- M. & P. C.
Reply: Here we add advice on sealing leaky electrical conduit on septic pump systems - below
A competent onsite inspection by an expert, or maybe in this case just an electrician, usually finds additional clues that help accurately diagnose a problem. That said, here are some things to consider:
What a fabulous detective job you've done, Thank you. I will be sure to add this odor source to the septic odor source diagnostic list [above]. Indeed we have discussed other reports of unanticipated air movement through electrical conduit - in Roger Hankey's article see section "Water Entry into Electrical Panel Case #3 - Negative Air Pressure & Moisture Condensation" ELECTRIC PANEL MOISTURE.
But we haven't previously discussed sewer gas or smells moving through conduit regarding septic systems or in your case septic pump systems. Here are two suggestions:
First, you should be able to seal both ends of the conduit with "duct seal putty" - basically a type of putty used by plumbers and electricians that is molded by hand and pushed into the opening. Available at any hardware store. Don't use glue or caulk or you'll make it tough when rewiring is needed.
Second, keep in mind what we learned in Hankey's article: negative air pressure at one end of a conduit can "suck" air or gases through the conduit from a distant source. In your case it's probably enough just to seal the 2 ends with putty - both ends because
Sealing the conduit ends is insurance against septic gas leaks that can be dangerous not just smelly
Sealing these leaks may also help avoid a potential sulphur-gas corrosion problem on any exposed copper wire portions of splices outside but near the conduit end
Repair Steps for sewer gases from remote pumping station
In Vermont this winter, frost is deep. Our tank for pumping spill over waste water from the settling tank to a sand mound is more than 100 feet from the house. We have a plastic underground conduit
running from the house to the pumping tank to provide electricity to the pump.
The pumping tank is buried under a dense and heavy snow/ice mound and has no ability to breath and let gas escape. It has no vent. I detected an ever increasing sewer gas (rotten egg) smell at the electrical box where the conduit pipe comes into the house in our basement.
Putting my nose by the conduit pipe end gives an overwhelming rotten egg smell. Even with functioning roof vents and wet traps (no smell there) sewer gas has found a least resistance path into the house. Immediate solution was to spray foam into the conduit.
Tomorrow I will dig the ice snow around the manhole cover in the pumping tank and give it a small opening to release gases. - R.K. 3/14/2014
This is a helpful report, R., and not the first time we've heard of sewer gases making their way back into a building through electrical conduit. I think you've got the right approach; I'd just add that when weather permits, on the pump end you might want to inspect to be sure that the conduit is sealed there too, against water entry as well as gases.
You may also want to check METHANE GAS SOURCES - other sources of methane gas in and around buildings
Watch out: we warn in all sewer or septic gas odor articles that because sewer gas contains
methane gas (CH4) there is a risk of an explosion hazard or even fatal asphyxiation.
Sewer gases also probably contain hydrogen sulfide gas (H2S) (HYDROGEN SULFIDE GAS). In addition some writers opine that there are possible
health hazards from sewer gas exposure, such as a bacterial infection of the sinuses (which can occur due to any sinus irritation).
Depending on the sewer gas source and other factors such as humidity and building
and weather conditions, mold spores may also be present in sewer gases
Continue reading at SEWER GAS ODORS or select a topic from the More Reading links or topic ARTICLE INDEX shown below.
Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Ask a Question or Search InspectApedia
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones
Support InspectApedia.com & See Fewer Advertisements
From Google's Contributor website: Contribute a few dollars each month. See fewer ads. The money you contribute helps fund the sites you visit.