Inactive Status, Permanent Closure, and Change in Service

To Place an Active UST system into Inactive Status

An owner or operator can place an UST system into Inactive Status by notifying the UST Section on the appropriate Notification of Inactive Status for Underground Storage Tanks Systems form that they have discontinued use of the system and wish the system to be considered inactive.

In addition, an owner/operator must:

  • Empty the tank to less than 1 inch of product (release detection is required until tank has less than 1 inch of product),
  • Cap and secure all product lines, sumps, manways, and ancillary equipment,
  • Leave vent lines open and functioning,
  • Continue to maintain corrosion protection (if applicable),
  • Continue to pay annual tank registration fees,
  • Continue to demonstrate financial responsibility by having the completed form on file at the facility,
  • Continue to have a trained Class A, Class B, and Class C Operator, and 
  • Conduct an inactive tank inspection every three years.
Rules regarding Inactive Status, Permanent Closure, and Change in Service can be found in Chapter 56 of Administrative Rules of Montana.

To Return an Inactive Tank System to Active Status

If an UST system has a valid Operating Permit and is in Inactive Status for 12 Months or Less

  • An owner or operator must give the department 30 days advance written notice of intent to return the UST to Active Status.

If an UST system has a valid Operating Permit and is in Inactive Status for 12 Months or More

  • An owner or operator must give the department 30 days advance written notice of intent to return the UST to Active Status, and;
  • Request a One Time Fill Permit
  • Perform a precision tank tightness test, line tightness tests and functionality tests of all mechanical and electronic release detection equipment, and submit all test results to the department. The owner or operator may return the UST system to active status only after the receipt of notice from the department indicating that the test results are satisfactory.

If an UST system does not have a valid Operating Permit and no more than 12 Months have passed since the expiration date of the last operating permit issued for the UST system

  • An owner or operator must give the department 30 days advance written notice of intent to return the UST to Active Status, and;
  • Obtain a Conditional Operating Permit from the department (expires 180 days later), and;
  • Have a compliance inspection conducted between 90 and 120 days after the Conditional Operating Permit is issued.

If an UST system does not have a valid Operating Permit and more than 12 Months have passed since the expiration date of the last operating permit issued for the UST system

  • An owner or operator must give the department 30 days advance written notice of intent to return the UST to Active Status, and;
  • Request a One Time Fill Permit for testing purposes only, and;
  • Perform a precision tank tightness test, line tightness tests and functionality tests of all mechanical and electronic release detection equipment, and submit all test results to the department. The owner or operator may return the UST system to active status only after the receipt of notice from the department indicating that the test results are satisfactory, and;
  • Obtain a Conditional Operating Permit from the department (expires 180 days later), and;
  • Have a compliance inspection conducted between 90 and 120 days after the Conditional Operating Permit is issued.

If an UST system does not have a valid Operating Permit and more than 3 years have passed since the expiration date of the last operating permit, and continuous operating and maintenance of corrosion protection cannot be demonstrated

  • An owner or operator must give the department 30 days advance written notice of intent to return the UST to Active Status, and;
  • Request a One Time Fill Permit for testing purposes only, and;
  • Show that the UST is structurally sound based upon a program-approved integrity assessment, and;
  • Perform a precision tank tightness test, line tightness tests and functionality tests of all mechanical and electronic release detection equipment, and submit all test results to the department. The owner or operator may return the UST system to active status only after the receipt of notice from the department indicating that the test results are satisfactory, and;
  • Obtain a Conditional Operating Permit from the department (expires 180 days later), and;
  • Have a compliance inspection conducted between 90 and 120 days after the Conditional Operating Permit is issued.

To Place a Tank System into Permanent Closure

At least 30 days before beginning permanent closure

  • An owner or operator must give the department advance written notice of intent to to permanently close. A closure permit application is an acceptable notification;
  • A closure permit may be obtained at DEQ, by calling (406)-444-5300, or by downloading the Closure Permit for UST Systems (PDF) from the web, and;
  • Empty and clean the UST by removing all liquids and accumulated sludge. All tanks and connected piping must be removed from the ground or, if approved by the department, filled with an inert solid material. The department does not generally approve closure in place unless removal from the ground endangers adjacent structures, and;
  • Conduct a site assessment in accordance with ARM 17.56.703.
  • For more information on closures, please visit our UST Closure Page

Change in Service

Continuing use of an UST system to store a non-regulated substance is considered a change in service. After a change in service, the tank is no longer regulated. No further annual registration fees will be assessed. No compliance inspection is required

  • To complete this procedure owners or operators must notify the department at least 30 days before making a change in service, and;
  • Empty and clean the UST system by removing all liquid, accumulated sludge and all combustible and flammable vapors, and;
  • Conduct a site assessment in accordance with ARM 17.56.703.