SSTS practitioner and homeowner information

Installation of Septic System

This page contains information for SSTS practitioners and homeowners on septic systems and onsite sewage treatment, system options, requirements for inspections, system operation and maintenance, and what to do when taking a septic system out of service (abandonment).

Local ordinances can vary from the state code, so it is important to always check with your local government (township, city or county) to determine the requirements in your area – MPCA local unit of government contacts.

The University of Minnesota has excellent resources for homeowner questions relating to SSTS. We refer you to your local unit of government or to the University of Minnesota Onsite Sewage Treatment Program, 1-800-322-8642 for homeowner information on septic systems.

Who to call

The SSTS staff page includes contact information and areas of responsibility.

Septic system options

Mound system installation; geotextile fabric and inspection pipes visible.

There are numerous onsite wastewater treatment systems available; site and soil conditions typically dictate the type of acceptable soil treatment system. Soil treatment systems include trenches, beds, at grades, and mounds. There are also advanced treatment products available; go to the product registration page for information – SSTS registered products.

Experience with septic system design and installation over the years has underscored the importance of carefully evaluating soil conditions and proximity to groundwater when choosing a treatment system that will work effectively over a long time. This is important to not only protect human health and the environment but also the significant investment homeowners make in their septic systems. When conditions call for installation of a mound system, homeowners can rest assured this technology works well, as proven by countless installations across the country over many years, including in Minnesota.

For more information about mound systems, see the publication and video links listed below. The video was produced by the Anne Arundel County (MD) Department of Health. While some of the terminology and requirements of the Maryland septic program are different than Minnesota’s, much is the same and this video does an excellent job of explaining how septic systems are installed, how they work and what homeowners can do to keep their septic system in operation for a long time.

Construction and inspections

Septic system inspections are required for all new construction and replacement (per local ordinance requirements). They are also required for any bedroom addition permit request if the local government issues building permits for bedroom additions. In Department of Natural Resources (DNR) Shoreland Areas, inspections are required for any building permit or variance request made to the local government. There is no statewide mandate for inspections at property transfer; however, many local ordinances and lending institutions do require compliance inspections.

The following fact sheets and forms are for inspections for existing systems (those systems subject to a compliance inspection) and for new system construction.

Property transfer and disclosure

Information on the requirements for septic system disclosure at property transfer (a state law requirement per Minnesota Statute §115.55, subd. 6) is contained in the fact sheet below. Disclosure of a septic system is not necessarily a compliance inspection. The option of requiring an SSTS compliance inspection when a home is sold is up to the local government; some have included this in their ordinances, others have not. For this reason, it is important to check local requirements before proceeding with a sale.

Operation and maintenance

Septic system maintenance will increase system life. The agency suggests that septic tanks be evaluated at least every three years and pumped out when sludge (settled mass) and scum (floating mass) accumulate to the point of endangering the soil treatment system. For some homes, the accumulation can take many years; in other homes this process may take less than a year. The accumulation depends entirely on how the system is used. For example, routine garbage disposal use will increase accumulation of material in the tank. Septic tank additives are not an alternative to pumping the accumulated solids from the tank.

Septic systems and flooding

This factsheet is provided to assist to property owners served by subsurface sewage treatment systems (SSTS or septic systems) on what to do before, during and after a flood.


When installing a replacement system, there is the question of what to do with parts of the old system that will no longer be used, such as sewage tanks. The MPCA recommends proper abandonment of all sewage tanks for public health and safety protection because tanks may collapse over time. Tank abandonment methods are prescribed in rule under SSTS system abandonment.