South Dakota Codified Laws
Chapter 12 - Home Rule Charters
Section 6-12-5 - Standards to be at least as stringent as state law.

6-12-5. Standards to be at least as stringent as state law.
Neither charter nor ordinances adopted thereunder may set standards and requirements which are lower or less stringent than those imposed by state law, but they may set standards and requirements which are higher or more stringent than those imposed by state law, unless a state law provides otherwise.

Source: SL 1974, ch 52, ยง5.