Statewide Portable Equipment Registration Program (PERP)

This page last updated September 14, 2015

image sample of portable equipment

Owners or Operators of portable engines and certain other types of equipment can register their units under the Air Resources Board's (ARB) Statewide Portable Equipment Registration Program (PERP) in order to operate their equipment throughout California without having to obtain individual permits from local air districts. The following sections will assist you with the PERP registration process and present facts on the Portable Diesel Engine Airborne Toxic Control Measure (ATCM).

IMPORTANT:  Please mail your PERP applications and other program correspondence to the address below.  Using the general P.O. Box for the Air Resources Board, or other addresses, will delay delivery.  Hand-delivered applications will no longer be accepted.  Also, there is no designated fax number for receiving PERP applications.  Faxing and mailing your application may result in duplicate charges to your credit card.  

P.O. Box 2038
Sacramento, CA 95812



Butte and Valley Fires:    Notification within 24 hours of operation is required for portable engines operating equipment where the portable engine is not permitted (if required), or registered in PERP, and the equipment is operating in support of fire-fighting and/or related clean-up activities in Amador and Calaveras counties (Butte Fire) and Lake and Napa counties (Valley Fire).  The notification form is available here and should be mailed to the above address, or sent via email when beginning operation at each location.

Drought Related Projects:   
Notification within 24 hours of operation is required for water well drill rigs, water pumps, or project-related equipment where the portable engine is not permitted, or registered in PERP, and is operating during California's drought emergency.  The notification form is available here and should be mailed to the above address, or via email when beginning operation at each project location.


On January 1, 2013, the Portable Engine Airborne Toxic Control Measure (ATCM) fleet emission standards went into effect.  The ATCM required owners of portable engines to submit a Fleet Compliance Report to the Air Resources Board by March 1, 2013.  For more information, click here:  Fleet Compliance Reporting.

The next Fleet Compliance Report will be due March 1, 2017.

Changes to Fleets

The ATCM also requires owners to ensure the average PM emission level for their fleet does not fall out of compliance due to changes in the fleet.  Owners of portable diesel engine fleets who are adding or removing engines are strongly encouraged to re-calculate their fleet average.  Other changes, such as modifying a registration to be low-use or emergency only-use can also affect the fleet emissions average.  We recommended that once you have completed the Fleet Reporting Tool save it and update it any time your portable fleet changes.

  • Diesel engine owners submitting applications for PERP registration for the first time must include a Fleet Compliance Report.  This includes transfer of existing registrations for engines you have purchased.
  • Contact us at if you have any questions regarding the fleet compliance requirements -- or see the contact list at the bottom of this page.


For initial registration into PERP, diesel engines must meet eligibility requirements as outlined below, or be a Flex engine certified under the flexibility provisions of Federal 40 CFR 1039.625, or 40 CFR Part 89.102, or California Code of Regulations section 2423 (d). 

Effective July 1, 2015

  • 50 to 74bhp - Final Tier 4
  • 75 to 174bhp - Interim Tier 4 (until further notice)
  • 175 to 749bhp - Final Tier 4
  • 750 and above - Interim Tier 4 (until further notice)

The PERP eligibility requirements take effect six months after the federal and CARB non-road engine emission standards for engine manufacturers change -- as shown here:  Non-road Diesel Engine Certification Tier Chart (PDF)

Engines on Two-Engine Vehicles

Frequently Asked Questions (FAQ)

  • The requirements for portable equipment can be complicated, so we have compiled a list of the most commonly asked questions with answers that may help you with this subject:  Portable FAQ document
  • A common question is raised about what constitutes portable versus stationary operation of equipment.  The PERP regulation defines portable operation and stationary sources however, there are some specific circumstances that, depending on each situation, the use of PERP-registered units may not be compatible with the objectives of PERP and those of local air districts.  Because such determinations are very fact dependent, we recommend you contact the district with questions about whether your portable equipment operation requires a district permit or can use PERP registration.  The California Air Pollution Control Officers Association (CAPCOA) has prepared a document which addresses these issues:  Explanation & Examples of Uses of PERP

Application Forms

  • Application Forms

  • Which Forms to Use

    Note:  PERP does not accept applications by Fax.  Please mail them directly to the address listed on the application forms or renewal invoice.

PERP Application Submittal Options:

Recordkeeping and Reporting Forms

Air District Notification

This is for notifying air districts for operation of registered equipment units (not engines).

  • Notification is required if an equipment unit (not an engine) will be at a location for more than five days. 


List Server and Contact Information

PERP Contact Information