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Sewer gas & methane gas questions & answers:
This article answers commonly-asked questions about methane gas hazards: dangers of explosion or asphytxiation from methane gas from various sources such as septic tanks and sewers.
This article series explains Methane Gas & Septic System Dangers from Gases, gives basic advice, and cites additional reference material.
This article is part of our Septic Safety article series that outlines safety warnings & procedures for septic systems and cesspools, and provides safety suggestions for septic system inspectors, septic system inspections, septic pumping contractors, and home owners.
Watch out: as we report at SEWER GAS ODORS, potentially explosive levels of gases can accumulate in a building from several sources including explosive levels of sewer gas, swamp gas, or fuel gas from a variety of possible sources including plumbing leaks, improper plumbing venting, LP or natural gas piping leaks or errors, or even swamp gas accumulation under a building.
Recently-posted questions & answers about methane gas hazards
On 2017-02-19 16:19:15.817070 by (mod) - explosion sounds from yard
Karyn, I cannot guess what may be making the sounds you describe. A methane gas explosion would be dramatic and would require both an accumulation of methane gas and a source of ignition - a spark or flame.
Before testing for methane I think an on-site inspection by an expert, or if you think there are actually explosions occurring, vacate the property and call emergency services immediately.
On 2017-02-19 11:13:02.923211 by Karyn
I keep hearing explosion like sounds outside my house. My septic system is outside and last year I had work done on it could this be related? Is there a test I can have done for gases to conclude that this is the reason for the noise?
On 2016-11-08 14:29:01.154835 by (mod) - building a block patio over the septic tank
The dangers I can suggest are outlined in the article above: creating a spark - and thus an explosion are immediate risks; I'd also want to be sure that not only is there easy access to all of the cleanout openings (there may be 3) but also to the tank ends and entire cover should later repair be needed.
If your "block" patio means simply dry-laid concrete blocks, and IF the septic tank cover is one rated as strong enough to support the weight and traffic involved you may be OK.
Be sure to avoid heavy traffic including machinery running over septic lines, tank, or over the drainfield.
On 2016-11-08 06:58:30.808990 by Bryan
I have a new house with a septic system. I want to build a block patio over the tank leaving access to the cover and use the patio for a fire pit area. Any dangers of gasses from the septic tank?
On 2016-07-31 14:17:02.882346 by (mod) - lingering methane gas problems
Interesting question and not one for which I've found expert advice. Perhaps if your outhouse floor plan includes a durable impermeable vapor barrier you'll avoid a potential methane hazard. In any event a generator cannot be safely run inside an enclosed space without fresh air and combustion air.
On 2016-07-30 17:12:51.172416 by Diane
I have a question about filling in an old outhouse. After we fill it in, we would like to convert the outhouse to our generator "doghouse." That would involve filling in the hole, covering the hole, insulating the room (to cut down noise), and adding some vents in the walls.
I'm wondering if there's any problem with potential lingering methane gas and using a gas-powered generator. Anyone have ideas/experience we should consider? Thanks!
On 2016-01-22 23:10:12.493973 by (mod)
It is common in many countries and communities to install plumbing that does not meet North American or European standards, including missing or inadequate venting; the risks are just what we think: poor drainage, sewer gas backup into the building, odors, and in some cases even an explosion risk.
Venting into an attic is also a bad idea: the vent needs to extend to outdoors not to dump sewer gas and moisture into an enclosed space.
I'd prefer to vent fixtures to the outdoors.
On 2016-01-22 06:48:38.118553 by Gene Pothier - methane gas hazards in the Philippines
I recently retired to the Philippines and purchased a home here and is under construction. During one of my routine inspections I noticed a few things that just did not seem correct to me with the plumbing.
Listed as follows (Please note: all homes here use a septic tank):
1) Sinks, toilets and shower drains have no vents.
2) Only source of venting is through the main drainage system which vents into the attic. Attic has no source of ventilation except from soffit openings at the 4 corners of the roof. There is no way for the heat to escape or any form of proper ventilation to take place and it does get hot here.
My question(s) is/are simple; as follows:
1) Does this pose a hazard of any kind? If so what are they? 2) Any suggestions as to a "fix" of improper plumbing?
My 1st question is the more important of the two as your reply will probably answer question 2.
Thank you in advance for any help/suggestions.
Gene Pothier Gene56_2006@yahoo.ca
On 2016-01-09 15:15:20.087215 by (mod)
Brian you ask an important question, not to mention the un-mentioned one of the very large volume of water being wasted daily.
One cannot answer the question without knowing not just what contaminants may be in the waste-water stream but also what pre-release treatment is going to be done to the wastewater before it is released to the environment.
Surely a project such as this one had to file an environmental impact statement - if you're in the U.S. - and that's a public document. Check with your local building authorities to ask where you can obtain a copy. Keep me posted.
Liu, Hong, Ramanathan Ramnarayanan, and Bruce E. Logan. "Production of electricity during wastewater treatment using a single chamber microbial fuel cell." Environmental science & technology 38, no. 7 (2004): 2281-2285.
Sharma, Yogesh, and Baikun Li. "Optimizing energy harvest in wastewater treatment by combining anaerobic hydrogen producing biofermentor (HPB) and microbial fuel cell (MFC)." International Journal of Hydrogen Energy 35, no. 8 (2010): 3789-3797.
Spiegel, Ronald J., and J. L. Preston. "Technical assessment of fuel cell operation on anaerobic digester gas at the Yonkers, NY, wastewater treatment plant." Waste Management 23, no. 8 (2003): 709-717.
On 2016-01-09 12:47:36.715232 by Brian
I live near a proposed fuel cell energy park. To convert the natural gas into hydrogen, the process will consume 300,000 gallons of water a day and discharge 150,000 gallons of wastewater to its wastewater infiltration system. Is this wastewater toxic? Will it give off any smell? Will it seep into our groundwater? I have a well; will it contaminate it?
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Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. Mr. Cramer serves on the ASHI Home Inspection Standards. Contact Mark Cramer at: 727-595-4211 mark@BestTampaInspector.com
John Cranor is an ASHI member and a home inspector (The House Whisperer) is located in Glen Allen, VA 23060. He is also a contributor to InspectApedia.com in several technical areas such as plumbing and appliances (dryer vents). Contact Mr. Cranor at 804-747-7747 or by Email: email@example.com
Hankey and Brown home inspectors, Eden Prairie, MN, technical review by Roger Hankey, prior chairman, Standards Committee, American Society of Home Inspectors - ASHI. 952 829-0044 - hankeyandbrown.com 11/06
Arlene Puentes, a licensed home inspector, educator, and building failures researcher in Kingston, NY. 11/29/06
John Francis, Bioworks, Inc., marketing and technical services - editing/proof reading 4/07. "BioWorks provides environmentally responsible, safe and cost-effective solutions to the agriculture industry"
Thanks to Denise Cermola for permission to use the photo above, showing a dump truck collapsed into a seepage pit. (email 11/16/06 to 12/10/06). The contractor drove over this seepage pit connected to septic tank and caused total destruction of the system.
Thanks to George Fielder who points out that methane gas is not toxic, but rather (we add) the hazards of methane gas produced by septic systems include possible explosions or the asphyxiation of someone who enters or even just leans over a septic tank opening. (email 10/20/2007)
"7 Killed by Blast in Mexico Resort", The New York Times, 15 November 2010, p. A9, reported (via AP) that in Playa del Carmen, Mexico, seven people were killed on 11/14/2010 when an explosion occurred in a large resort hotel in Mexico south of Cancun. Twelve others were injured. Authorities believed that swamp gas may have accumulated under the hotel that was constructed on a concrete slab over a swampy area near the beach.
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf.
Pennsylvania State Fact Sheets relating to domestic wastewater treatment systems include
Pennsylvania State Wastewater Treatment Fact Sheet SW-161, Septic System Failure: Diagnosis and Treatment
Pennsylvania State Wastewater Treatment Fact Sheet SW-162, The Soil Media and the Percolation Test
Pennsylvania State Wastewater Treatment Fact Sheet SW-l64, Mound Systems for Wastewater Treatment
Pennsylvania State Wastewater Treatment Fact Sheet SW-165, Septic Tank-Soil Absorption Systems
Document Sources used for this web page include but are not limited to: Agricultural Fact Sheet #SW-161 "Septic Tank Pumping," by Paul D. Robillard and
Kelli S. Martin. Penn State College of Agriculture - Cooperative Extension, edited and annotated by
Dan Friedman (Thanks: to Bob Mackey for proofreading the original source material.)
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Advanced Onsite Wastewater Systems Technologies, Anish R. Jantrania, Mark A. Gross. Anish Jantrania, Ph.D., P.E., M.B.A., is a Consulting Engineer, in Mechanicsville VA, 804-550-0389 (2006). Outstanding technical reference especially on alternative septic system design alternatives. Written for designers and engineers, this book is not at all easy going for homeowners but is a text I recommend for professionals--DF.
Builder's Guide to Wells and Septic Systems, Woodson, R. Dodge: $ 24.95; MCGRAW HILL B; TP;
Quoting from Amazon's description: For the homebuilder, one mistake in estimating or installing wells and septic systems can cost thousands of dollars. This comprehensive guide filled with case studies can prevent that. Master plumber R. Dodge Woodson packs this reader-friendly guide with guidance and information, including details on new techniques and materials that can economize and expedite jobs and advice on how to avoid mistakes in both estimating and construction. Chapters cover virtually every aspect of wells and septic systems, including on-site evaluations; site limitations; bidding; soil studies, septic designs, and code-related issues; drilled and dug wells, gravel and pipe, chamber-type, and gravity septic systems; pump stations; common problems with well installation; and remedies for poor septic situations. Woodson also discusses ways to increase profits by avoiding cost overruns.
Country Plumbing: Living with a Septic System, Hartigan, Gerry: $ 9.95; ALAN C HOOD & TP;
Quoting an Amazon reviewer's comment, with which we agree--DF:This book is informative as far as it goes and might be most useful for someone with an older system. But it was written in the early 1980s. A lot has changed since then. In particular, the book doesn't cover any of the newer systems that are used more and more nowadays in some parts of the country -- sand mounds, aeration systems, lagoons, etc.
Design Manuals for Septic Systems
US EPA Onsite Wastewater Treatment Systems Manual [online copy, free] Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm Onsite wastewater treatment and disposal systems,
Richard J Otis, published by the US EPA. Although it's more than 20 years old, this book remains a useful reference for septic system designers.
U.S. Environmental Protection Agency, Office of Water Program Operations; Office of Research and Development, Municipal Environmental Research Laboratory; (1980)
"International Private Sewage Disposal Code," 1995, BOCA-708-799-2300, ICBO-310-699-0541, SBCCI 205-591-1853, available from those code associations.
"Manual of Policy, Procedures, and Guidelines for Onsite Sewage Systems," Ontario Reg. 374/81, Part VII of the Environmental
Protection Act (Canada), ISBN 0-7743-7303-2, Ministry of the Environment,135 St. Clair Ave. West, Toronto Ontario M4V 1P5 Canada $24. CDN.
Manual of Septic Tank Practice, US Public Health Service's 1959.
Onsite Wastewater Disposal Books
Onsite Wastewater Disposal, R. J. Perkins;
Quoting from Amazon: This practical book, co-published with the National Environmental Health Association,
describes the step-by-step procedures needed to avoid common pitfalls in septic system technology.
Valuable in matching the septic system to the site-specific conditions, this useful book will help you install a reliable system in
both suitable and difficult environments. Septic tank installers, planners, state and local regulators, civil and sanitary engineers,
consulting engineers, architects, homeowners, academics, and land developers will find this publication valuable.
Onsite Wastewater Treatment Systems, Bennette D. Burks, Mary Margaret Minnis, Hogarth House 1994 - one of the best septic system books around, suffering a bit from small fonts and a weak index. While it contains some material more technical than needed by homeowners, Burks/Minnis book on onsite wastewater treatment systems a very useful reference for both property owners and septic system designers.
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf
Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000 $14.95 U.S. - easy to understand, well illustrated, one of the best practical references around on septic design basics including some advanced systems; a little short on safety and maintenance. Both new and used (low priced copies are available, and we think the authors are working on an updated edition--DF.
Quoting from one of several Amazon reviews: The basics of septic systems, from underground systems and failures to what the owner can do to promote and maintain a healthy system, is revealed in an excellent guide essential for any who reside on a septic system. Rural residents receive a primer on not only the basics; but how to conduct period inspections and what to do when things go wrong. History also figures into the fine coverage.
Grass is Always Greener Over the Septic Tank, Bombeck, Erma: $ 5.99; FAWCETT; MM;
This septic system classic whose title helps avoid intimidating readers new to septic systems, is available new or used at very low prices.
It's more entertainment than a serious "how to" book on septic systems design, maintenance, or repair. Not recommended -- DF.
US EPA Onsite Wastewater Treatment Systems Manual Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm
Water Wells and Septic Systems Handbook, R. Dodge Woodson. This book is in the upper price range, but is worth the cost for serious septic installers and designers.
Quoting Amazon: Each year, thousands upon thousands of Americans install water wells and septic systems on their properties. But with a maze of codes governing their use along with a host of design requirements that ensure their functionality where can someone turn for comprehensive, one-stop guidance? Enter the Water Wells and Septic Systems Handbook from McGraw-Hill.
Written in language any property owner can understand yet detailed enough for professionals and technical students this easy-to-use volume delivers the latest techniques and code requirements for designing, building, rehabilitating, and maintaining private water wells and septic systems. Bolstered by a wealth of informative charts, tables, and illustrations, this book delivers:
* Current construction, maintenance, and repair methods
* New International Private Sewage Disposal Code
* Up-to-date standards from the American Water Works Association
Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF.
Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.
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.
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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