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Subpart 1.


This chapter provides design standards for ISTS that exclusively receive sewage. If ISTS receive both sewage and nonsewage, the requirements of this chapter and requirements governing the nonsewage portion of the waste apply.

Subp. 2.

System influent.


Footing or roof drainage and chemically treated hot tub and pool water must not be discharged into any part of a system. Products containing hazardous chemicals and hazardous waste must not be discharged to a system other than in normal amounts of household products and cleaners designed for household use. Substances not intended for use in household cleaning, including but not limited to solvents, pesticides, flammables, photo finishing chemicals, paint, and dry-cleaning chemicals must not be discharged to the system. Other unused products or substances, or unused medicines, must not be discharged to the system solely as a method of disposal. Floor drains from garages serving dwellings must not be connected to the system.


An ISTS must be designed to provide additional treatment if:


raw sewage exceeds 300 mg/l BOD, 200 mg/l TSS, or 50 mg/l oil and grease; or


sewage tank effluent applied to the soil from the sewage tank or other secondary treatment device is greater than the concentrations in part 7080.2150, subpart 3, item K.

Additional treatment must be designed by a Minnesota licensed professional engineer or according to the recommendations in the Prescriptive Designs and Design Guidance for Advanced Designers, which is incorporated by reference in item C, or must use a product registered under chapter 7083.


Prescriptive Designs and Design Guidance for Advanced Designers, Minnesota Pollution Control Agency (September 2009 and as subsequently amended), is incorporated by reference, is subject to frequent change, and is available at

Statutory Authority:

MS s 115.03; 115.55


32 SR 1347; 35 SR 1353

Published Electronically:

October 10, 2013

700 State Office Building, 100 Rev. Dr. Martin Luther King Jr. Blvd., St. Paul, MN 55155 ♦ Phone: (651) 296-2868 ♦ TTY: 1-800-627-3529 ♦ Fax: (651) 296-0569