What are the regulations pertaining to retaining walls heights and location?

The Code specifically exempts retaining walls four feet or lower in height from the requirement for a building permit as long as it is not supporting a surcharge. Examples of a surcharge would be a driveway with vehicle traffic located near the top of the wall or a condition where the wall supports base of a hill with significant slope and length. Retaining walls less than four feet high, if

regulated, should only be regulated by a "Zoning" or “Miscellaneous" permit. (Ref. MN Building Code Sec. 1300.0120 Subp. 4 (4).

Any retaining wall within 10 feet of any property line shall require a certificate of survey illustrating the location of any retaining wall or fence in relation to the property line.