U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3011

January 2006

In cooperation with the West Virginia Department of Health and Human Resources, Bureau for Public Health, 

Office of Environmental Health Services, Environmental Engineering Division, and the 

West Virginia Department of Environmental Protection, Division of Water and Waste Management

Methane in West Virginia Ground Water

Printed on recycled paper

Introduction

Methane has been found as a dissolved gas in numerous ground-water 

samples from water wells in West 

Virginia. Methane (CH4) is a colorless, 

odorless, tasteless gas that can cause 

oxygen-deficient atmospheres, flammable situations, or explosive environments. Methane can ignite at atmospheric 

concentrations between 5 and 15 percent, 

and higher concentrations of methane 

can quickly dilute to flammable levels. 

Thus, the accumulation of methane gas in 

an enclosed area may cause an explosive 

environment in which an ignition source 

such as an electrical outlet, pilot light, 

match, or even a well pump could trigger 

a violent explosion. In addition to the 

obvious hazards associated with explosions, the breathing of methane in high 

concentrations can lead to asphyxiation, 

and the burning of methane produces 

toxic gases (Eltschlager and others, 

2001). 

Potential sources of methane gas, 

also referred to as natural gas, firedamp, and marsh gas, include active 

and abandoned coal mines, improperly 

constructed gas wells, decaying organic 

matter, landfills, and swamps. Methane is 

often generated and stored in sedimentary 

rocks associated with coal beds and with 

oil and gas fields. Coal-bed methane is a 

result of the microbial or thermal alteration of organic matter during coal formation. The methane originates in the coal 

units or often in carbonaceous shales, but 

it may migrate to other geologic units 

conducive to storage, such as overlying, 

permeable sandstones (Eltschlager and 

others, 2001).

Methane gas can be transported 

by ground water in dissolved or pure 

gaseous states. Methane in ground water 

is not explosive; but when water containing dissolved methane comes into 

contact with air, the methane quickly 

escapes from the ground water into the 

atmosphere. If this process occurs in a 

confined space, then the methane could 

ignite; or if it is allowed to accumulate, it 

could explode. Because the solubility of 

methane in water is between 28 and 30 

mg/L (milligrams per liter), well water 

samples with concentrations of dissolved 

methane greater than 28 mg/L could liberate potentially explosive or flammable 

quantities of gas inside the well or in confined spaces in well houses or structures 

containing wells. Concentrations of methane greater than 10 mg/L but less than 

28 mg/L are a possible indication that 

methane concentrations may be increasing to dangerous levels in ground water 

(Eltschlager and others, 2001). 

Occurrence and Distribution 

of Methane in West Virginia 

Ground Water

From 1997 to 2005, the USGS 

sampled ground water using standard 

sampling protocols (Koterba and others, 

1995) from 170 wells in West Virginia 

for dissolved gases, including methane. 

Replicate dissolved-gas samples were 

collected for each well; the averaged dissolved-gas concentrations for each well 

are reported in White and Mathes (2006), 

and averaged methane concentrations are 

described herein. Methane concentrations 

in ground water for the 170 wells ranged 

from not detected to 68.5 mg/L. Methane was detected in 131 of 170 of these 

wells and was present in concentrations 

greater than 28 mg/L in 13 of these wells. 

Another 13 wells had methane concentra-
tions ranging from 11.9 to 24.3 mg/L, 32 

wells had concentrations ranging from 

1.00 to 10.0 mg/L, and 73 wells had 

detectable methane concentrations less 

than 1.00 mg/L. Methane was detected in 

wells in 43 of the 47 counties sampled, 

but methane concentrations exceeding 

10 mg/L were found in wells in only 11 

counties, with 22 of 26 of these samples 

from eight counties located in the southern coal fields of West Virginia. All but 

three of these samples were south of the 

“hinge line” (Arkle, 1969) that separates 

the lower-sulfur coal deposits of southern 

West Virginia from the higher-sulfur coal 

deposits of northern West Virginia. Most 

(23 of 26) of the samples with methane 

concentrations greater than 10 mg/L were 

from wells with water-bearing zones in 

rocks of Pennsylvanian age, with one 

sample from Permian age rocks, one 

sample from Mississippian age rocks, and 

one sample from Devonian age rocks. 

No samples with methane concentrations 

greater than 10 mg/L were found in Quaternary alluvium or in rocks older than 

Devonian age (table 1). Methane concentrations exceeding 10 mg/L were found in 

wells located in valleys and on hillsides 

but not in wells located on hilltops.

Action Levels

 The U.S. Department of the 

Interior, Office of Surface Mining 

(Eltschlager and others, 2001), advises 

owners of wells with dissolved methane 

concentrations greater than 28 mg/L to 

immediately contact their local county 

health department to obtain assistance 

and guidance in venting the wellhead and 

for other possible remediation alternatives. Methane will not accumulate in the 

wellbore if the well is properly vented 

to the air. Owners of wells with methane 

concentrations greater than 10 mg/L but 

less than 28 mg/L might also wish to contact their local county health department 

for further assistance and might consider 

removing ignition sources from the 

immediate area. Methane concentrations 

less than 10 mg/L require no action, other 

than periodic monitoring to see if methane concentrations are changing. The 

West Virginia Bureau for Public Health 

advises that private well owners requiring additional information about methane 

contact their local county health department. Public water supply systems in West 

Virginia are advised by the West Virginia 

Bureau for Public Health to contact one of 

the following West Virginia Department of 

Health and Human Resources, BPH-EED 

District Offices:

Beckley (304) 256-6666

Kearneysville (304) 725-9453

Philippi (304) 457-2296

St. Albans (304) 722-0611

Wheeling (304) 238-1145

or the central Charleston BPH-EED 

office at (304) 558-2981.

References Cited

Arkle, Thomas, Jr., 1969, The configuration of the Pennsylvanian and Dunkard 

(Permian?) strata in West Virginia; 

a challenge to classical concepts, in

Donaldson, A.C., ed., Some Appalachian coals and carbonates—Models of 

shallow water deposition, Preconvention Geological Society of America 

Field Trip, November 1969: West 

Virginia Geological and Economic 

Survey, p. 55–88. 

Eltschlager, K.K., Hawkins, J.W., Ehler, 

W.C., and Baldassare, Fred, 2001, 

Technical measures for the investigation and mitigation of fugitive methane 

hazards in areas of coal mining: Office 

of Surface Mining Reclamation and 

Enforcement, 125 p.

Koterba, M.T., Wilde, F.D., and Lapham, 

W.W., 1995, Ground-water data-collection protocols and procedures for the 

National Water-Quality Assessment 

Program–Collection and documentation of water-quality samples and 

related data: U.S. Geological Survey 

Open-File Report 95–399, 133 p.

White, J.S., and Mathes, M.V., 2006, Dissolved-gas concentrations in ground 

water in West Virginia: U.S. Geological Survey Data Series 156, 8 p., available online at http://pubs.water.usgs.

gov/ds156/

—M.V. Mathes and J.S. White

For Additional Information

For information on USGS products and 

services, call 1-888-ASK-USGS or visit 

the ask.usgs.gov Web site or the USGS 

home page at http://www.usgs.gov/.

Table 1.  Distribution of methane with respect to geologic age.

Geologic age of waterbearing rocks

Number of samples with the indicated methane 

concentrations (in milligrams per liter)

>28 10.1–28 1.00–10.0 <1.001 Not 

detected

Quaternary alluvium 0 0 0 9 2

Permian 0 1 1 4 3

Pennsylvanian 11 12 26 35 13

Mississippian 1 0 1 15 6

Devonian 1 0 3 9 8

Silurian No wells sampled

Ordovician 0 0 0 0 7

Cambrian 0 0 1 1 0

 Total samples 13 13 32 73 39

1

All detections of methane with concentrations less than 1.00 milligram per liter.