Methane Soil Gas Survey


Methane Soil Gas Survey


The purpose of a Methane Soil Gas Survey is to test a property for subsurface methane and hydrogen sulfide hazards, in order to determine the proper methane mitigation design parameters for future development.

Methane is a colorless and odorless gas that can migrate underground (through soil and structure foundations), and accumulate inside buildings. Accumulations of these gasses are associated with oil and gas fields, natural gas extraction wells, coal mines and landfills. Awareness on the hazards of methane soil gas rises from methane gas explosions in Los Angeles during 1985. Since then, various building departments and public works agencies recommend a methane soil gas survey and/or a mitigation plan within specific methane hazard zones.

After methane testing has been completed at a job-site, a methane mitigation plan is prepared in effort to eliminate the hazards of methane  gas intrusion. In addition to methane testing, Geo Forward, Inc. also provides methane mitigation design services and methane mitigation plans for all types of construction projects.

Call us at (888) 930-6604 to speak with a licensed geologist and get a free estimate!  


Where are Methane Soil Gas Surveys Needed? 

Methane Soil Gas Survey "The first oil district in Los Angeles, Toluca Street, ca.1895-1901"

The first oil district in Los Angeles, Toluca Street, California.1895-1901 (CHS-3686)

During the late 1800s and early 1900s, oil and gas production was predominantly practiced in central and southern California. The northernmost areas of California were primarily used for natural gas production.

In recent years, the City of Los Angeles established high-risk “Methane Zones” which require methane soil gas surveys before undergoing construction or demolition. Various public works entities are beginning to follow the same standards.  Citywide methane mitigation requirements can be reviewed in Ordinance No. 175790 and Ordinance No. 180619.

Unincorporated cities in Los Angeles County fall under the jurisdiction of the Los Angeles County Methane Mitigation Unit, and generally require methane soil gas surveys on construction sites within 1,000 feet of a landfill or 300 feet of a oil & gas well. Please Click Here to view the County of Los Angeles Building Code.

Huntington Beach and other portions of Orange County also require a methane soil gas survey to assess methane risk.


Typical Soil Gas Probe Set schematic for a Methane Soil Gas SurveyBuilding Department Methane Soil Gas Surveys

Geo Forward offers methane and hydrogen sulfide testing services to meet the requirements of all building jurisdictions in California. Our sampling and testing plans include determining site design level, locating nearby zone boundaries or hazards, installing soil gas probes, and air quality analysis. A standard methane soil gas survey tests the shallow soil gas underlying a property, for fast results from the field.


Limited Methane Soil Gas Surveys for Real Estate Due Diligence 

When a comprehensive methane soil gas survey is NOT required by the local building departments, property owners can request a limited methane test for due diligence and risk assessment.  In such cases, Geo Forward offers Limited Methane Soil Gas Surveys.  If the findings of a limited test warrant a follow-up comprehensive methane test, the costs can be credited towards the comprehensive scope.


Methane Soil Gas Survey Probe Set

Photo by: Azad Kaligi

Methane Mitigation Plans 

Local building departments may also require methane mitigation plans to reduce health-related dangers such as asphyxiation or explosion.  Geo Forward offers a variety of methane mitigation services in all areas of California. Click here to learn more about Methane Mitigation Plans/Reports. 


For more information about methane testing or mitigation, please call (888) 930-6604 to speak with a licensed professional geologist, engineer or environmental scientist. 


Sources of Information:
U.S. EPA
U.S. EPA Guidance for Methane Landfill Gas Sampling & Testing
City of Los Angeles, Department of Building & Safety
The Methane Zone – The Land Developer’s Guide

Geo Forward, Inc.

Forward-Thinking Geologists, Engineers & Contractors!

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