St. Martin Parish, LA Noise Ordinances: Decibel Limits (2026)

Section 26-37(a) sets the continuous sound limits, measured at any location at or within the property line of the receptor property: 60 decibels for property zoned residential between 7:00 a.m. and 10:00 p.m. inclusive, 50 decibels for property zoned residential between 10:00 p.m. and 7:00 a.m., and 70 decibels for property zoned commercial or industrial, with no day and night split. Section 26-34 defines continuous sound as any sound lasting more than one second, measured with a sound level meter set to slow response, and defines "decibel" as sound pressure level on the "A" weighting network with slow meter response as specified by the American National Standards Institute. Section 26-36 applies the article to sound originating from or received by any property in the unincorporated areas and states that it applies equally to all properties regardless of permitted land use or zoning classification.

Impulsive sound, a single pressure peak or burst lasting less than one second, gets its own test under section 26-37(b). From 7:00 a.m. to 10:00 p.m., impulsive sounds occurring less than ten times in an hour cannot equal or exceed 20 decibels above the subsection (a) level, and impulsive sound that repeats ten or more times in an hour cannot exceed the subsection (a) level itself. From 10:00 p.m. to 7:00 a.m., the same two tiers apply at less than four times and four or more times in an hour.

Section 26-37(d) reduces the subsection (a) limits by five decibels when a mechanical device emits a steady tone, a whine, hum or buzz, whose measured level does not fluctuate by more than plus or minus three decibels. Heating, ventilating and air conditioning units, refrigeration units and transformers are listed examples, and residential HVAC units cannot exceed 55 decibels after 9:00 p.m. Section 26-39 adds separate rules: power tools and yard equipment on residential property are off between 10:00 p.m. and 6:00 a.m.; construction and demolition stop between 10:00 p.m. and 6:00 a.m. on weekdays and between 10:00 p.m. and 8:00 a.m. on weekends and federal holidays; and animals cannot make more than 60 vocalizations in any ten-minute period. Section 26-38 exempts properly muffled agricultural activities, emergency work, aircraft, public celebrations and events within a Parish Council variance, among other sources.