Storage Tanks

Tank owners are required to register their tanks with the MPCA. Owners of regulated underground storage tanks (USTs) and above ground storage tanks (ASTs) must report information such as tank age, size, and contents within 30 days after installation of a new tank, or within 30 days after any changes in tank ownership, use, or contents. The agency provides forms for this purpose. Septic tanks and some pipeline facilities are excluded from tank regulations but are regulated under other rules.

The MPCA must receive 10 days advance notice, in writing, prior to the installation, removal, or repair of regulated USTs. Only MPCA certified contractors can perform UST installation, repairs and removal projects. The agency provides a list of these certified contractors. Contractors are not required to be certified or provide advance notice for installation, removal, or upgrade of ASTs or non-regulated USTs. However, individuals and companies doing AST work must follow applicable standards outlined in Minnesota Rules, Chapter 7151. MPCA does not regulate USTs with a capacity of 110 gallons or less, residential or farm USTs storing 1,100 gallons or less of motor fuel (used for non-commercial purposes), and USTs storing 1,100 gallons or less of heating oil (used to heat the property where the tank is located).

Underground Storage Tanks (Usts)

According to Minnesota Rules, Chapter 7150, most new and existing regulated USTs must have spill, overfill, and corrosion protection. USTs that do not have these safeguards must immediately be taken out of service and either, replaced, removed, or abandoned-in-place with fire marshal approval. Regulated USTs were required to have leak detection on or before 1993 based on the age of the tank.

All new underground tanks, as well as any associated piping must be double-walled and fuel dispensers, and submersible pump heads, must have a secondary containment design, meaning a liquid-tight barrier to capture and detect leaks. Existing piping, fuel dispensers and submersible pump heads, when repaired may require replacement.

For double-walled tanks, you will need to check monthly for liquids in the interstice between the walls, and document the check. If the interstice has a continuous automatic liquid sensor withalarm, you will just need to perform an annual function check of the sensor.

Drop tubes extending to within 12 inches of the tank floor are required for all tanks. New gasoline tanks must have a drop tube extending to within six inches of the tank floor if the facility has greater than 10,000 gallons monthly throughput.

Secure anchoring of breakaway valves under dispensers must be maintained.

Monthly checks of all sump areas (fill pipe spill buckets, submersible pump sumps, and underdispenser sumps) are now required. If you have a submersible pump sump with liquid-tight containment and a liquid sensor alarm that is function tested annually, then the sump may be checked annually. Checking the sump means lifting the lid and looking for spilled or leaked product, water, or debris, and cleaning out the sump if necessary. Keep a record of sump checks. A checklist is available from the MPCA, or owners can make their own.

All automatic line leak detectors must be function tested annually. Testers must be MPCAcertified contractors, have received testing approval from the manufacturer, or be specifically qualified by reason of training or experience. Owners may not perform the tests unless they are qualified. Obtain the test result record from the contractor and keep it. A publication, What Tank Owners need to know about the New Underground Storage Tank Rules ( is available from MPCA.

If you have an impressed current type of cathodic protection system, then the system’s rectifier must be checked every 60 days. Check that current is being delivered and record the volt and amp readings. Owner-operators may do this. A corrosion expert must inspect the system for effective protection at least annually.

If your cathodic protection is sacraficial anode they must be tested every three years. If your system is designed with external testing stations, the three-year tests and post-repair tests may be performed by the owner/operator, using a voltmeter. Record and maintain the results. External test stations must test all piping as well; if they are not designed to do this, use a qualified cathodic protection tester.

If you have a high level alarming system for protection during tank fills it must be audible to the fill driver. It is recommended that the alarm be tested for proper function at least annually, and must be audible to the fill operator.

For tanks with internal linings, due to lining failure concerns, these tanks must be emptied, entered, and internally inspected by a qualified third-party inspector at least every five years. New requirements cover pre-notification, inspection techniques, and reporting. Very minor repairs are allowed; however, if the lining ever fails, the tank must be permanently closed.

After days of inactivity, temporary closure is required. This means the tanks must be completely emptied and a notification form must be filed with the MPCA. Any rectifier must be kept on, and any cathodic protection system must be tested every year or three years, as applicable. After one year of inactivity, the tank owner must request and receive written approval to extend the temporary closure period, otherwise the tanks must be permanently closed. This means closedin-place (filled with an inert substance) or removed from the ground. After five years of inactivity, all tanks must be permanently closed.

Prior to closing the transaction of selling or purchasing property with USTs, the seller must notify the purchaser of the purchaser’s duty to notify the MPCA. Purchaser must file a notification form with the MPCA for the change in ownership, and must certify that all operators, including lessees, have read the UST rules and know how to operate and maintain UST systems.

Above Ground Storage Tanks (Asts)

With a few exceptions, all new and existing AST facilities with a total storage capacity of less than one million gallons must have corrosion protection, overfill protection, secondary containment, and substance transfer area protection according to Minnesota Rules, Chapter 7151. Monitoring and leak detection requirements also exist for these ASTs. Some tanks excluded from these regulations include farm ASTs, ASTs with a capacity of 500 gallons or less, residential ASTs storing 1,100 gallons or less of motor fuel (used for non commercial purposes), and ASTs storing 1,100 gallons or less of heating oil (used to heat the property where the tank is located).

If an AST holds more than 10,000 gallons, a spill response plan is required. This plan describes the steps the tank owner will take if there is a spill or another type of accident. Call the MPCA at the telephone number listed in the Resource Directory of this Guide for the content requirements of a spill response plan.

AST facilities with total storage capacity of greater than or equal to one million gallons must obtain an individual permit for their tanks. The individual permit addresses tank inspection and maintenance, spill containment, tank gauging, overfill protection, corrosion protection, and tank upgrades. Permits are issued for up to five years. To obtain an individual site permit for your facility, please call the MPCA’s AST program.

Tank owners and operators can participate in an environmental audit program. This program allows tank owners to make improvements to their site before fines or violation notices are issued or enforcement action is taken. The environmental audit cannot be used at facilities where serious and repeat violations have occurred.

More information about tanks is available by calling the MPCA or by reviewing the MPCA website at Click on programs and select “Aboveground Storage Tank Systems” or the “Storage Tank Compliance and Assistance Program”.

Water Quality Requirements

Businesses may need a permit or certificate from the MPCA if they:

  1. Discharge any wastewater into surface waters (including storm sewers);
  2. Operate an agricultural feedlot;
  3. Operate a disposal system which land-applies wastewater, or by product;
  4. Operate a large on-site drain field; or
  5. Operate any one of a class of categorical industries.
  6. Discharge storm-water from an industrial or construction site.
  7. Plan to dredge, fill, inundate or drain a wetland to the extent that a United States Army Corps of Engineers permit would be required. The MPCA must then certify that permit.

Businesses requiring an extension of a sanitary sewer system will be affected by the MPCA requirement that any municipality must have a Sewer Extension Permit before extending its sanitary sewer lines. For more details, please see the MPCA factsheet found at, then click on Permits, then click on Water Permits. There is a sewer extension permit application fee.

CREDITS: This is an excerpt from A Guide to Starting a Business in Minnesota, provided by the Minnesota Department of Employment and Economic Development, Small Business Assistance Office, Twenty-eighth Edition, January 2010, written by Charles A. Schaffer, Madeline Harris, and Mark Simmer. Copies are available without charge from the Minnesota Department of Employment and Economic Development, Small Business Assistance Office.

This post is also part of a series of posts on Minnesota Environmental Protection Programs and how they affect starting a business in Minnesota.