American Gas Association 

Summary of Current Leak Survey Requirements 

May 12, 2010 

Federal Leak Survey Regulations

U.S. Department of Transportation (DOT) 

Pipeline & Hazardous Substances Safety Administration (PHMSA) 

49 C.F.R. Part 192 Pipeline Safety Regulations for Natural Gas Transmission & Distribution 

See attached chart for all applicable DOT regulations. 

In brief, DOT requires utilities to conduct leak surveys of gas distribution systems: 

1. Once per year in business districts annually and 

2. Once every 5 years outside business districts. 

See 49 C.F.R. §192.723. 

State Utility Commission Leak Survey Regulations

Some state PUCs adopt the federal DOT rules. Connecticut and Nevada are 

examples.

Others impose more stringent than federal requirements for surveying and 

grading leaks. Survey intervals in these states range from once every 3 years to 

every year.

Example of more stringent state rules: California PUC Rule Section 143.1 Leak Surveys 

must be conducted “at intervals not exceeding 15 months, but at least once each 

calendar year.” 

California PUC Rule Section 143.2 Valve maintenance similarly provides: 

“Each valve, the use of which may be necessary for the safe operation of a distribution 

system, must be inspected, serviced, lubricated (where required) and partially operated 

at intervals not exceeding 15 months, but at least once each calendar year.”

 List of Components to be inspected under DOT and state PUC leak survey rules:

The DOT regulations do not list specific components to be inspected. 

There is no requirement to maintain “counts” of specific types of components. Some of our 

member companies have developed such counts for purposes of voluntary greenhouse gas 

inventories, such as CCAR or the Climate Registry, however these companies have not 

developed component counts for all the components listed in proposed Subpart W. 

DOT Rules provide in 49 C.F.R. §192.723 -- “The type and scope of the leakage control 

program must be determined by the nature of the operations and the local conditions.” 
2

State PUC Rules may be more specific. But there is no state requirement to count the number 

of valves or other types of components. 

Leak Detection Methods:

DOT rules require the use of “leak detector equipment.” See 49 C.F.R. §192.723. This 

includes the full range of options, such as soap solution, wands, optical scanning. 

State PUC Rules may be more specific.

For example, Maryland PUC Rules require the following: 

“A. Procedures and Methods. Each utility or gas master meter operator shall establish 

procedures for making periodic gas leakage surveys as specified in these regulations. For 

residential customers with meters located outdoors, leakage surveys shall be performed up to 

the building entry. The leakage surveys shall be conducted by one or more of the following 

methods:

(1) Flame ionization; 

(2) Combustible gas indicator and bar hole; 

(3) Optical methane detector; or 

(4) Other method approved by the Commission. 

AGA GPTC Leak Survey Guidelines and Company Leak Survey Plans

AGA’s Gas Pipe Technology Committee (GPTC) has developed guidelines for conducting leak 

surveys based on DOT PHMSA requirements. Member companies have developed their leak 

survey plans based on the GPTC Guidelines, adding any more stringent requirements imposed 

by the applicable state PUC. The AGA GTPC Guidelines are available for purchase for a small 

fee at www.aga.org . AGA can provide EPA with some sample excerpts from the GPTC 

Guidelines. 

In addition, we will provide some sample member company leak survey plans. 

How Utilities Must Respond and Report:

Immediate Reports to DOT and State for Serious Leaks: In the case of an emergency level 

leak, called an “incident,” the operator must respond and address the leak immediately. The 

operator also must report the incident to DOT and state regulators within two hours. 

Annual Leak Report to DOT: The incidents and other leaks discovered during the year must 

also be reported to DOT on the operator’s annual report.