Statewide Portable Equipment Registration Program (PERP)

This page last updated November 5, 2018

new button  2018 REGULATORY UPDATES

  • The new Portable Equipment Registration Program Regulation and the Portable Diesel Engine Airborne Toxic Control Measure (ATCM) will be effective November 30, 2018. On the effective date, the new Regulation and ATCM will be posted to our webpage for public viewing. Until then, you can view the Board approved Regulation and ATCM here.
  • Effective November 30th the Portable Equipment Registration Program will have a new invoice and refund policy. Please download and view the policy here
  • Please download and view the PERP 2018 Regulatory and Program Changes Booklet.
  • Effective November 30th, any person selling a certified engine subject to the Portable ATCM in California must provide a Disclosure of Applicability (ATCM 93116.3 (f)). CARB has approved language for a Combined Disclosure of Applicability for Truck and Bus, Off-Road, and PERP.
  • Due to the regulatory changes, the PERP webpage will be going offline November 29th and will return November 30th. 

image sample of portable equipmentOwners 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).

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. Faxed and hand-delivered applications are no longer accepted.

P.O. Box 2038
Sacramento, CA 95812


Notification within 24 hours of operation is required for project-related equipment where the portable engine and/or equipment unit is not permitted or registered in PERP, and is operating during a declared emergency event. The notification form is available here and should be mailed to the above address, or via email when beginning operation at each emergency event location.

Drought Related Projects:  Executive Order B-40-17 lifts the drought emergency in all California counties except Fresno, Kings, Tulare and Tuolumne, where emergency water-well drilling projects will continue to help address diminished groundwater supplies. For on-going and/or future groundwater projects in California counties other than the four listed above where portable equipment will be used, please contact the local air district for air quality permitting information.


Please review the revised Regulatory and Enforcement Advisory and its related Q&A regarding the upcoming amendments to the 2017 and 2020 Portable Diesel Engine ATCM fleet average emission standards.

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.

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-use only 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.


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).

  • 50 to 74bhp - Final Tier 4

  • 75 to 174bhp - Final Tier 4

  • 175 to 750bhp - Final Tier 4

  • greater than 750 - 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

PERP Contact Information

Write to:

Email Statewide Portable Equipment Registration Program (PERP)
P.O. Box 2038
Sacramento, CA 95812

List Serve and Contact Information

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.

  • Online notification