Businesses with SSTS, Class V, small communities and cluster systems: Regulatory and other considerations

There are other considerations when installing an SSTS for facilities serving more than 3 single family home or establishments having a flow greater than 2500 gallons per day.


A system that is designed to manage a flow of greater than 10,000 gallons per day is reviewed and permitted by the MPCA. Local units of government typically review designs and issue construction permits for SSTS designed for 10,000 gallons per day or less. The Minnesota Department of Health (or designated local health department) reviews and approves designs for systems that serve health care facilities.

There are certain criteria that need to be met when designing an LSTS. Flow determination, site evaluation, treatment, drainfield sizing, septic tank sizing, and sewer system design are addressed in these documents.

Permits issued by the MPCA include monitoring and reporting requirements as well as proper operation and maintenance of the system. For more information, please refer to the following fact sheets:

Advanced design guidance

Holding Pond

All sizes of Type IV SSTS (systems with advanced treatment), and all SSTS with a flow of 2,501 gallons per day to 10,000 gallons per day need to be designed by an Advanced Design business with some components needing to be designed by AELSLAGID professionals. Below are Prescriptive Standards and Design Guidance that Advanced Designers must follow in designing the above mentioned systems.

Class V: Underground Injection Control: Class V Systems

Class V systems are defined as:

Business Septic Systems are Class V Injection Wells, regulated by the state ISTS rules and US EPA from their Chicago office.

All Class V wells need to be inventoried with EPA. Below is the link to EPA's registration form and instructions on how to complete it:

Two kinds of Class V wells are banned nationwide; those at vehicle maintenance shops and community cesspools. New ones are prohibited, and those in wellhead protection areas were required to be closed in January 2007.

Existing Class V wells at vehicle maintenance shops not located within wellhead protection areas do not need to close according to EPA’s rules. They do need to VERY CLOSELY scrutinize what is going down those wells. All hazardous waste in the shops must be managed in accordance with Minnesota’s Hazardous Waste requirements.

If your vehicle maintenance shop can’t discharge to city sewer or to a septic system (Class V well), what can you do?

There are other types of business septic systems and EPA has requirements for them as well.

If you have questions about the EPA program, it’s best to contact the EPA:

Federal UIC - Class V Contacts:

Unsewered and undersewered communities

Unsewered exampleUndersewered areas have inadequate wastewater treatment, where existing wastewater treatment methods are not adequate to protect public health or the environment. The situations range from failing individual systems to cities with inadequate collection and treatment infrastructure.

Unsewered areas do not have centralized wastewater collection and treatment, where wastewater collection is not done through a large sewer system.

There are other state rules relating central sewer systems to SSTS, including:

Livestock Operations


Professional registration (engineers, soil scientists, geologists, surveyors)