Boone County, IN Noise Ordinances: Decibel Limits (2026)

Section 157.036 sets performance standards for all industrial uses in Boone County's Industrial zoning districts, covering smoke, odor, toxic materials, glare, vibration and, in division (F), noise: no industrial use may exceed 70 decibels at a residential or business district boundary line, and the noise must be muffled so it is not objectionable for intermittence, frequency or shrillness. Construction and maintenance activity, ordinary vehicle operation, and safety or emergency alarms are exempt under division (G). For a specific conditional use, a machine shop, Section 157.061(F) sets a stricter 45-decibel ceiling for the manufacturing or fabricating work itself, measured at the property line and excluding loading, unloading and transportation noise; if a neighbor complains, an acoustical engineer or audiologist must measure the sound with an audiometer and report to the Area Plan Commission.

Both standards sit in the zoning code, so they are enforced as zoning matters rather than through the county's separate nuisance-based noise ordinance in Chapter 92, which instead bars 'plainly audible' noise during set hours rather than setting a decibel number.