Photo of a TIF 8800 combustible gas analyzer being used to check a kitchen sink drain for sewer gas leaks How to Test for & Trace Sewer Gas Smells and Septic Tank Odors in a Building

  • TEST FOR INDOOR SEWER GAS - CONTENTS: Sewer gas & odor testing: how to use the TIF 8800 or similar combustible gas analyzers to test for and trace the source of sewer gas or septic gas or methane gas leaks in buildings
    • Detailed procedure and recommendations for using the TIF8800 to check for sewer or septic gases & similar odors in buildings
  • SEWER GAS ODORS - home
  • POST a QUESTION or READ FAQs about how to track down sewer gas or septic odors in buildings

This article describes how to How to Test for & Trace Sewer Gas Smells and Septic Tank Odors in a Building or how we might trace "gas odors" in buildings with a focus on homes with a private onsite septic tank or for owners whose home is connected to a public sewer system as well. What makes the smell in sewer gas? Sewer gases are more than an obnoxious odor.

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Tests for Indoor Sewer Gas & Septic Odors - Indoor Gas Leaks using the TIF 8800 Combustible Gas Analyzer

Gas leaks at plumbing vent (C) Daniel FriedmanWatch out: 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)

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.

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Tests for sewer gas or septic odor gas leaks: When looking for gas leaks and tracking gas smells, one method to get more precise is to use an instrument sensitive to a broad range of combustible organic gases.We use a TIF 8800 combustible gas analyzer set at its most sensitive setting to sniff for gas leaks.

Our photo at above left illustrates a type of hidden and subtle source of sewer gas odors in buildings: defects in the building drain, waste, or vent piping that are hidden in wall or ceiling cavities.

This particular leak is discussed at DRAIN PIPING & SEWER ODORS .

This instrument will respond to a very wide range of volatile organics, including pipe dope on a plumbing joint, so be careful.The TIF8800 will also respond a little to the gases found at almost any plumbing drain since the trap is often producing some organic gases.

But if you find that there is one drain that responds unusually strongly, or if you find a leak in a fuel gas line, you've found a problem to correct before going further.Many home inspectors have this tool and can be hired to apply it carefully in your home, or it may be less costly (than hiring an inspector) to just buy the tool itself.

Here are some ways we use the TIF 8800 to screen for and trace sewer gases in a building

  • Turn on the instrument outside (not near a busy highway or running vehicle) and enter the building to screen for the detection of any combustible gas;
  • Enter each building area with the instrument freshly-set to outdoor ambient air conditions
  • Don't forget to try the sensor tip at different heights indoors - warm air rising can carry flue gases or other combustibles to unanticipated areas higher than the gas source
  • Adjust the instrument to its most sensitive setting, using its response sound to move towards stronger sources of any gas that has been detected.
  • Remember to check not only plumbing drains but gas fittings
  • Remember that the presence of organic solvents in some pipe joint compounds may make the instrument respond even though no leak may be present
  • Confirm that the instrument is responding to gases by testing it such as in or near a (not too hot) heating flue, gas source, or preferably, using the sensing tip calibrating vial provided by the manufacturer.

Also see TIF 8800 GAS DETECTOR for a detailed procedure of how this instrument is employed and for a list of gases to which it will respond.

Watch out: The use of most test instruments gives only an instantaneous indicator of a substance that is present at the time of the test and in the location tested. Tests for individual substance or even individual classes of substances are never a complete assurance of building conditions, as other substances not within the scope of the test may be present.

And instrument tests are never a sure indicator that hazardous substances are not present or have not been present at other times or under different building conditions. Never rely only on the results of test instruments when examining a building for unsafe conditions such as gas leaks.

Expert visual inspection of the building exterior, interior, and mechanical systems as well as an understanding of the building's damage, leak, and repair history and of the vulnerability of particular construction designs and materials are all important considerations when evaluating the condition of a structure.

Other Tests for Methane Gas (besides the TIF 8800)

Certainly there are quite a few (often more expensive) instruments that can test for combustible gases, and there are gas-specific tests that address methane-only. For general use a broad-spectrum test instrument such as the TIF8800 discussed here offer the advantage of sensitivity to a wide range of gases, increasing the chance of detecting a concern when the instrument is used, and also increasing the chance of confusion about just what gas is present.

At TIF 8800 GAS DETECTOR we provide details about the use of the instrument described in the article above.

At Drager GAS DETECTORS we describe a simple pump instrument that can, by selecting the proper detector tube, test for a very large range of individual gases at various concentrations.

Other types of gas detection instruments are discussed at GAS DETECTION INSTRUMENTS

For readers interested in monitoring specifically for methane gas, perhaps as an indicator of sewer gas leaks, take a look at the Xintex Methane Gas Detector S2B-M-X, described by its manufacturer as follows:

The Xintex® Methane Gas Detector / Monitor, Model S2B-M-X-Display-D, constantly monitors the level of highly explosive methane and goes into alarm prior to a dangerous situation occurring. This advanced micro-processor, state of the art, Methane Gas Detector is incorporated into the design and re-design of vehicles using CNG or LNG as a fuel.  

The company offers other methane gas detection systems as well, including sensors designed to react to specific elevated levels of methane and natural gas.

Watch out: when buying any gas detection instrument be sure to compare the detection and reporting range of the instrument with the level of concern that you need to address. Otherwise dangerous conditions may exist without detection.

  • Fireboy®- Xintex® Inc P.O. Box 152 · Grand Rapids, Michigan USA 49501-0152 O-379 Lake Michigan Dr NW · Grand Rapids, MI USA 49534 Phone: 616-735-9380 Fax: 616-735-9381 Toll-free: 866-350-9500 Website:
  • European inquiries: Fireboy- Xintex, LTD Unit 10 Holton Road · Holton Heath Industrial Estate · Poole, Dorset · BH16 6LT · UK Phone: +44 (0) 845 389 9462 Fax: +44 (0) 1202 625376 Email Registration No. 05789560 England Reg. Office 14 New Street, London EC2M 4HE, United Kingdom

Sewer Gas Detection Research

  • Barsky, J. B., SS Que Hee, and C. S. Clark. "An evaluation of the response of some portable, direct-reading 10.2 eV and 11.8 eV photoionization detectors, and a flame ionization gas chromatograph for organic vapors in high humidity atmospheres." The American Industrial Hygiene Association Journal 46, no. 1 (1985): 9-14.
  • Beardsley, C. W., N. J. Krotinger, and J. H. Rigdon. "Removal of sewer odors by scrubbing with alkaline solutions." Sewage and Industrial Wastes (1958): 220-225.
  • Dincer, Faruk, and Aysen Muezzinoglu. "Odor determination at wastewater collection systems: Olfactometry versus H2S analyses." CLEAN–Soil, Air, Water 35, no. 6 (2007): 565-570.
  • Fan, Chi-Yuan, Richard Field, William C. Pisano, James Barsanti, James J. Joyce, and Harvey Sorenson. "Sewer and tank flushing for sediment, corrosion, and pollution control." Journal of Water Resources Planning and Management 127, no. 3 (2001): 194-201.
  • Frechen, Franz-Bernd, and Wulf Köster. "Odour emission capacity of wastewaters—standardization of measurement method and application." Water Science and technology 38, no. 3 (1998): 61-69.
  • Guisasola, Albert, David de Haas, Jurg Keller, and Zhiguo Yuan. "Methane formation in sewer systems." Water Research 42, no. 6 (2008): 1421-1430.
  • Hurwitz, L. J., and GwenethI Taylor. "POISONING BY SEWER GAS: WITH UNUSUAL SEQUELÆ." The Lancet 263, no. 6822 (1954): 1110-1112.
  • Kim, Jihyoung, Jung Soo Lim, Jonathan Friedman, Uichin Lee, Luiz Vieira, Diego Rosso, Mario Gerla, and Mani B. Srivastava. "SewerSnort: A drifting sensor for in-situ sewer gas monitoring." In Sensor, Mesh and Ad Hoc Communications and Networks, 2009. SECON'09. 6th Annual IEEE Communications Society Conference on, pp. 1-9. IEEE, 2009.
  • Koo, Dae-Hyun, and Samuel T. Ariaratnam. "Innovative method for assessment of underground sewer pipe condition." Automation in Construction 15, no. 4 (2006): 479-488.
  • LUO, Yong, Xiao-bo MAO, and Jun-jie HUANG. "Development of Infrared Methane Sensor." Instrument Technique and Sensor 8 (2007): 001.
  • Marrin, Donn L. "Soil‐Gas Sampling and Misinterpretation." Groundwater Monitoring & Remediation 8, no. 2 (1988): 51-54.
  • Pandey, Sudhir Kumar, Ki-Hyun Kim, and Kea-Tiong Tang. "A review of sensor-based methods for monitoring hydrogen sulfide." TrAC Trends in Analytical Chemistry 32 (2012): 87-99.
  • Stuart, R. D. "Weil's disease in Glasgow sewer workers." British medical journal 1, no. 4076 (1939): 324.
  • Watt, Monika M., Stephen J. Watt, and Anthony Seaton. "Episode of toxic gas exposure in sewer workers." Occupational and environmental medicine 54, no. 4 (1997): 277-280
  • YANG, Jing, Wei-zhen LIANG, and Qing-qiang MENG. "Monitoring Method for the Combustible and Poisonous Gas from Urban Sewer [J]." China Water & Wastewater 1 (2005): 026.



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