Mobile Home Parks

The Safety and Enforcement Division (SED) is responsible for ensuring the safety of mastered metered natural gas systems in mobilehome parks. SED inspects mobilehome parks that take natural gas service through a master meter and then distribute it to park residents through their own system of underground pipes.

SED also inspects systems where liquefied petroleum gas (LPG), i.e. propane, is distributed from a master tank through underground pipes to multiple customers. SED has jurisdiction over Propane Master Tank systems serving two or more customers inside a mobilehome park or 10 or more customers in residential or commercial districts.

SED currently inspects over 2100 mobilehome park operators and 600 propane operators on a minimum seven-year risk-based schedule. Inspections consist of reviewing operation and maintenance records, evaluating emergency procedures, and performing field inspections of the gas or propane systems.

What regulations must a small natural gas or propane system operator follow?

  • Each operator must prepare and follow a manual of written procedures for conducting the following activities:
    • Operations and Maintenance
    • Emergency Response
    • Operator Qualification
    • Distribution Integrity Management
  • Each operator must also keep all records required by the above procedures to be reviewed by SED inspectors.
  • Each year, each operator must submit an annual report to SED describing their system, the number of customers, and the dates of the most recent leak survey and cathodic protection survey.

       Blank MHP Annual Report Form

       Blank Propane Annual Report Form

 How to prepare an Operations and Maintenance (O&M) plan:  Title 49 CFR 192, Section 192.605 requires each operator to prepare a manual of written procedures for conducting operations, maintenance, and emergency activities.  GSRB has prepared a sample Guidance Manual to help small operators prepare their own Operation, Maintenance and Emergency (OM&E) Plan, Operator Qualification (OQ) Program, and Distribution Integrity Management Program (DIMP). This guide provides information on what is required to be included in your plans. Many outside vendors also can help you prepare the OM&E Plan, OQ Program, and DIMP.  

2014 Guidelines for Preparing OM&E Plans, OQ Plan, & DIMP for MHP Gas Systems

2012 Guidelines for Preparing OM&E Plans, OQ Plan, & DIMP for Propane Gas Systems




To help small utilities and operators, the U.S. Department of Transportation - Pipeline and Hazardous Materials Safety Administration publishes guidance manuals for operators of small natural gas and propane systems.

Each year, the GSRB presents seminars to operators of small gas systems on how to comply with the federal regulations.

The Western Manufactured Housing Communities Association (WMA) represents the interests of owners of mobilehome parks.  Please visit their website to find a list of pipeline service providers.

The Western Propane Gas Association (WPGA) represents the interests of marketers of propane

The Golden State Manufactured-Home Owners League (GSMOL) represents the interests of people who live in mobilehomes



Public Utilities Code, Sections 4351 through 4360 gives the California Public Utilities Commission (Commission) jurisdiction over the safety of master-metered natural gas systems in mobilehome parks. In January 1995 the Commission also assumed jurisdiction over the safety of  propane master tank distribution systems. Assembly Bill 766 (Hauser) adopted Public Utilities Code, Sections 4451 through 4465 giving the Commission jurisdiction over Propane Master Tank systems serving 10 or more customers not in a mobilehome park or two or more customers inside a mobilehome park. The Gas Safety and Reliability Branch (GSRB) of the Commission enforces Federal Pipeline Safety Regulations through audits of jurisdictional MHP and Propane Master Tank systems.  Audits consist of reviewing operation and maintenance records, evaluating emergency procedures, and performing field inspections of the gas distribution facilities. If violations are found, the operator is given an inspection form requesting that corrective measures be taken within a specified time.  If the operator complies and reports the corrective actions to the inspector, the inspection is closed.  If the operator fails to comply, a citation and fine may result. 

In resolution SU-24, dated 12/17/1993 the Commission delegated authority to GSRB to cite and fine MHP operators for failure to comply with pipeline safety regulations. Resolution USRB-001 dated July 31, 2008 delegated similar authority for operators of propane master tanks.  These fines are not to exceed $1,000 per day and $200,000 per violation. In levying fines, GSRB considers a number of factors including the gravity of the offense and the operator's history of compliance. There is an appeal process.

Public Utilities Code Section 2791 put a stop to the construction of master metered mobilehome parks.  It requires that residents of mobilehome parks built after January 1, 1997 be directly served by the gas and electric utilities serving in that area.  Sections 2791 through 2799 outline a process by which existing master metered mobilehome parks can be converted to direct utility service.  GSRB encourages such conversions.  Because the serving utilities are exclusively in the business of providing gas and electric service, a consistently high standard of maintenance and safety is assured.  Benefits to operators of master metered parks include relief from complying with increasingly complex and demanding federal pipeline safety regulations and equally complex requirements for rendering bills for service.  

The Commission assumed jurisdiction over the safety of master metered propane distribution systems in January 1995, as mandated by Assembly Bill 766 (Hauser).  The Commission's Utilities Safety Branch administers the propane safety program similar to its Mobilehome Park Safety Program, scheduling each jurisdictional system for a safety inspection at least once every five years, to assure compliance with the federal pipeline safety regulations adopted by the Commission under General Order 112-E.

The GSRB is required by Section 4353(b) to inspect the gas facilities of MHPs at least once every seven years pursuant to a risk-based inspection schedule. Over 2,800 MHPs are currently under the jurisdiction of the Commission. Section 4453(b) requires GSRB to inspect Propane Master Tank Systems once every seven years pursuant to a risk-based inspection schedule. Over 600 propane operators are currently contained in the Commission's database.

On 8/1/2008, the Commission approved a resolution giving authority to GSRB staff to cite those propane operators who fail to abide by the Commission directives.

User fees:  The Commission is a user-funded agency and it collects fees based on the number of customers served by the master metered MHP or propane system.  These fees are included in the master meter bill for natural gas customers and may be passed through to the submetered customers.  The GSRB bills propane master tank systems annually at the time it mails the annual report.


The CPUC is currently conducting an extended Mobile Home Park Utility Upgrade Pilot Program to convert master-metered gas and/or electric facilities to direct utility service.  Decision D20-04-004 established a 10-year MHP Upgrade Program, with new applications being accepted beginning January 1, 2021.  GSRB is currently working with utility companies to establish a timeline for the roll-out of the new program.

 For more details on the program, please click on the following link: 


January 11, 2021: Master-Meter Natural Gas Distribution Systems Exempted From DIMP/SHRIMP Requirements Effective March 12, 2021
A recent change to Title 49 of the Code of Federal Regulations (CFR) exempts master-meter operators from the requirements for a Distribution Integrity Management Program (DIMP) described in 49 CFR Part 192, Sections 192.1003, 192.1005, and 192.1015. The new rule goes into effect on March 12, 2021. Beginning on that day operators of master-metered natural gas distribution systems will no longer need to have DIMP plans. All other gas maintenance and operation requirements affecting master-meter operators remain in place.

To view the changes in its entirety, you can visit:


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