When having a septic system installed in MN you need to remember that soils in Minnesota can very and a licensed septic system design contractor needs to design your septic system.

Septic system in Wright County are mostly mound system s because of heavy clay soils. Some of the cities that apply to this statement are Buffalo, Maple Lake, Annandale, Clear Water, Rockford, St Michel and Albertville.  In Hennepin County near Rogers, Dayton and Corcoran have a heavy clay soil as well.

If you live in the Monticello, the Otsego area, some parts of write county you will find sandy soils where most septic systems are in ground systems.  Becker clear Lake  Zimmerman up to Princeton  following through the elk river Ramsey , Anoka , East Bethel, Ham Lake, and Andover area  usually have in ground system unless they are in a low wetlands area

Some of the most even soil I have seen has been around Wadena County. This soil is consistent compared to most. The most verging soils we have seen has been in Park Rapids, Nevis, Akley, Lake George areas, in Hubbard county.

In Anoka County  there are special cases where different soils pushed in by the glaciers that formed deposit s of different soils in deferent  areas like a hill of sand where everything around is clay. But as a rule of thumb  look at your soil type dig down about 2 feet  if its sand  and on high ground (not near swamps ) you can problem get by with an in ground system.  If you have clay soil you will probably need a mound septic system. The easiest way to find out for sure the size and type of septic system you need is to have a septic system designer design one for you. A septic system designer is required by the state of MN before a septic permit is issued.