NOTICE: The Tank Site Improvement Program is not accepting new applications (including non-preapproved reimbursement requests for confirmation of suspected releases) during Fiscal Year 2025 (July 1, 2024 – June 30, 2025). 

The following list describes the eligible actions under the Tank Site Improvement Program and examples of costs that are and are not eligible for reimbursement.

In addition to the following, review the list of common examples of ineligible costs that apply to all actions | View List >

Confirmation of a Suspected Release

Investigation to determine whether or not there has been a release to the environment. The more quickly a leak is identified, the less the contamination spreads and the less costly it should be to clean up.

Example of costs eligible for reimbursement:

• Environmental sampling (“site check”) activities

Example of costs not eligible for reimbursement:

• UST system/equipment testing

UST Removal

Older systems may have greater potential to leak. Removing these systems from the ground provides an opportunity to identify potential areas of contamination and improve leak prevention by replacing with a new UST that meets current industry standards and may be better for today's fuel blends.

Examples of costs eligible for reimbursement:

• Removal of UST systems, including tanks and piping
• Environmental sampling required for site assessment
• If field observations indicate a release of petroleum into the environment and over-excavation is required to remove impacted soil, TSIP allows reimbursement up to $15,000 per site for over-excavation of petroleum contaminated media

Examples of costs not eligible for reimbursement:

• Permanent closure of tanks not regulated by ADEQ’s UST program, such as above-ground storage tanks or vaulted USTs
• Removal and/or replacement of dispensers, canopy, or other structures
• In-place permanent closure unless supported by documentation provided from an Arizona registered professional structural engineer

Note: ADEQ has developed a tool to assist with estimating soil volumes for excavation and backfill, as well as the number of stockpiled samples required under PCS regulations | Download Tool (Excel) >

UST Replacement

New installations are required to comply with all current state and federal standards. 

Example of costs eligible for reimbursement:

• Installation of a new UST system to replace a UST system that was removed, includes tanks, piping, under-dispenser containment, leak detection, etc.

Examples of costs not eligible for reimbursement:

• Installation of dispensers, which are not considered part of the UST system
• Installation of USTs at new sites (sites that do not have existing USTs) where there would be no environmental risk reduction
• Replacement of canopies or surface structures

UST Modification

UST system modifications must ensure that the resultant UST system complies with all current state and federal standards.

Examples of costs eligible for reimbursement:

• Replacement of single walled piping to double walled piping
• Installation of under-dispenser containment for UST systems with double-walled tanks and piping

Examples of costs not eligible for reimbursement:

• Actions that will not result in the system meeting new UST installation standards (for example, lining the interior of UST systems)
• Installation of dispensers, which are not considered part of the UST system
• Modifications to canopies or surface structures

Baseline Assessment

Baseline assessments are investigations of likely release areas to identify contamination and determine whether the operating UST system may be leaking. They require the collection of environmental samples, a professional registrant’s interpretation regarding confirmation of a previously unknown release and an evaluation of potential risk.¹ If a new release is identified, there must be an evaluation of whether the current UST system may be an ongoing source of contamination. This information may be useful to an owner or operator who is looking to reset the retroactive date for their UST insurance coverage.

Examples of costs eligible for reimbursement:

• Collection of environmental samples, such as soil or groundwater
• A professional registrant’s interpretation regarding confirmation of a previously unknown release and an evaluation of potential risk

Example of costs not eligible for reimbursement:

• Routine UST system testing

¹For a more comprehensive description of baseline assessments, consult Arizona Revised Statutes § 49-1052 | View >