Waste Programs Division: Underground Storage Tanks
Tank pull

An underground storage tank (UST) system is a tank and any underground piping connected to the tank that has at least ten percent of its combined volume underground. Federal and State UST regulations apply only to underground tanks and piping storing either petroleum or certain hazardous substances.

ADEQ's Waste Programs Division ensures proper operation and maintenance of regulated underground storage tank systems by conducting periodic inspections and assisting owners and operators in complying with applicable state and federal regulations. Enforcement actions are taken in cases of significant non-compliance. The division also protects public health and the environment through oversight, investigation and cleanup of soil and groundwater contamination caused by releases from underground storage tanks.

The UST Program regulates the majority of USTs in Arizona, with the exception of those on Indian lands. Nearly all underground storage tanks at these sites contain petroleum. These sites include marketers who sell gasoline to the public (such as service stations and convenience stores) and non-marketers who use tanks solely for their own needs (such as fleet service operators and local governments).

What is "Petroleum"?

Under Arizona Revised Statutes (A.R.S.) § 49-1001: "Petroleum" means petroleum, including crude oil or any fraction of crude oil, which is liquid at sixty degrees Fahrenheit and 14.7 pounds per square inch absolute, and petroleum based substances comprised of a complex blend of hydrocarbons derived from crude oil through processes of separation, conversion, upgrading and finishing, such as motor fuels, residual fuel oils, lubricants, jet fuels, distillate fuel oils, petroleum solvents and used oils.

What is a "Regulated UST?"

Under A.R.S. § 49-1001: "Underground storage tank" means a tank or combination of tanks and underground pipes and impact valves connected to tanks being used or having been used to contain regulated substances and which has at least ten per cent of the total volume of the tank and underground portions of pipes connected to the tank underground. Underground storage tank does not mean any of the following:

  • A farm or residential tank of one thousand one hundred gallons or less capacity used for storing motor fuel for noncommercial purposes.
  • A tank used for storing heating oil for consumptive use on the premises where stored.
  • A septic tank.
  • A pipeline facility, including gathering lines, regulated under either:
    • The natural gas pipeline safety act of 1968 (49 United States Code sections 1671 through 1686).
    • The hazardous liquid pipeline safety act of 1979 (49 United States Code section 2001).
  • An intrastate pipeline facility regulated under a state law comparable to the provisions of law referred to in subdivision (d), item (i) or (ii).
  • A surface impoundment, pit, pond or lagoon.
  • A storm water or wastewater collection system.
  • A flow-through process tank.
  • A liquid trap or associated gathering lines directly related to oil or gas production and gathering operations.
  • A storage tank situated in an underground area, such as a basement, cellar, mine working, drift, shaft or tunnel, if the storage tank is situated on or above the surface of the floor.
  • Pipes connected to any of the structures described in subdivisions (a) through (j).

Compliance with these and other operational and administrative requirements is the responsibility of the UST Program.

Links Within the UST Program

Contact Us LUST Stakeholder Meeting Information
Delivery Prohibition Public Notices
Financial Responsibility State Assurance Fund
Forms and Guidance State Lead Program
Inspections & Compliance UST Policy Commission and Technical Appeals Panel
Leaking UST Investigations & Cleanups UST Database Search
Leaking Underground Storage Tank Enforcement Unit Video Gallery

Delivery Prohibition

On January 1, 2009 Arizona Revised Statute (ARS) § 49-1023 gave ADEQ the authority to issue a stop use order to the owner and operator of an Underground Storage Tank (UST) system if the UST is in violation of Arizona's UST rules and regulations and the continued operation of the UST may result in a continued release or a new release from the UST. The stop use order becomes effective immediately on issuance and suspends the use of the underground storage tank until the owner and operator has returned the UST to full compliance with Arizona's UST rules and regulations.

More information on delivery prohibition and stop use orders may be found in Arizona Revised Statute (ARS) § 49-1023 Leaving ADEQ Web site.

Facilities currently under a stop use order have delivery prohibition in effect. Facilities will be removed from this list within five business days after the department determines that the requirements in Arizona Revised Statute (ARS) § 49-1023 have been met.

Facility Name: Mercado de Amigo
Facility Location: 1529 N. Avenue 64E, Dateland, AZ
Stop-Use Order Issue Date: July 15, 2014
Underground Storage Tank Affected: All tanks at this site are subject to delivery prohibition. They are as follows:
  • UST number 1: A 8,000 gallon, single compartment, gasoline UST
  • UST number 2: A 8,000 gallon, single compartment, diesel UST
Facility Name: Killmer's Kountry Store
Facility Location: 115 Highway 188, Globe, AZ
Stop-Use Order Issue Date: July 11, 2014
Underground Storage Tank Affected: All tanks at this site are subject to delivery prohibition. They are as follows:
  • UST number 1: A 10,000 gallon, single compartment, gasoline UST
  • UST number 2: A 10,000 gallon, single compartment, diesel UST
Facility Name: One Stop 2
Facility Location: 379 South Main Street, Snowflake, Navajo County, Arizona
Stop-Use Order Issue Date: March 16, 2012
Underground Storage Tank Affected: All tanks at this site are subject to delivery prohibition. They are as follows:
  • UST number 6: A 10,000-gallon, single compartment, gasoline UST
  • UST number 9: A 2,000-gallon, single compartment, gasoline

Back to the top of the page


Video Gallery

Fountain Hills Soil Vapor Sampling

Located approximately thirty miles northeast of downtown Phoenix, Fountain Hills, Arizona is known for the towering man-made fountain located in the center of town. ADEQ was there, working in a residential neighborhood near an elementary school as part of its State Lead underground storage tank program. The Lead program is so named because ADEQ assumes the responsibility for corrective actions where the responsible party is unknown, unwilling, or unable to undertake site investigations and cleanups. The purpose of testing soil vapor is to determine whether there is any risk to public health from the contaminated groundwater beneath the area. Twenty years ago there was a gas station across the street from the school that leaked contaminants into the soil and water. If there is contamination that requires cleanup, ADEQ will work to mitigate the risk so the public will be safe. The work is paid for by the penny-per-gallon tax on all fuels sold within Arizona.

Red Rock UST Removal

Located between Phoenix and Tucson off Interstate 10, Red Rock, Arizona is a mostly an agricultural area, although the city has recently seen construction of tract home communities. ADEQ was at an abandoned gas station as part of their State Lead program, so named because ADEQ takes charge of the underground storage tank removal and assessment for possible soil and groundwater contamination because the property has been abandoned. At this site, ADEQ removed three 8,000 gallon steel tanks used for gasoline storage and one 550 gallon tank used to house used oil in order to adequately assess contamination risks. If there is contamination that requires cleanup, ADEQ will work to mitigate the risk so the area can be redeveloped.