South Dakota state law: decibel limits

Unlike states with statewide noise codes (e.g., New Jersey N.J.A.C. 7:29 or Minnesota Rule 7030), South Dakota Codified Laws do not establish a numeric decibel standard at residential property lines, do not require dBA measurement equipment for enforcement, and do not specify dBA measurement protocols (slow vs. fast response, L10 vs. Leq, microphone height). The statewide floor is SDCL 22-18-35: 'A person is guilty of disorderly conduct if the person, with intent to cause public danger, alarm, disorder, or nuisance or knowing that such would be the probable result of such person's conduct... makes unreasonable noise.' Disorderly conduct is a Class 2 misdemeanor. SDCL 21-10-1 supplies the civil-nuisance test ('annoys, injures, or endangers the comfort, repose, health, or safety of others'). Municipalities adopt specific decibel caps under SDCL 9-29-1 (general welfare) or, for Sioux Falls / Rapid City / Watertown, under SDCL 6-12 home-rule charter authority. Typical adopted thresholds: 55 dBA daytime and 50 dBA nighttime at residential property line; 65 dBA daytime and 60 dBA nighttime at commercial property line.

SDCL 22-18-35 disorderly conduct (Class 2 misdemeanor): up to 30 days jail and up to a $500 fine. Municipal decibel violations typically: civil fines of $100 to $500 per occurrence, escalating for repeat violations. Equipment subject to confiscation in some city codes.