New Haven, CT Noise Ordinances: Decibel Limits (2026)

Section 18-75 sets a matrix of maximum decibel levels measured at the property line, keyed to both the zone where noise originates (the 'emitter's zone') and the zone that receives it (the 'receptor's zone'). A residential emitter is capped at 62 dBA when noise crosses into an industrial zone, 55 dBA into a commercial zone, 55 dBA into another residential zone by day, and 45 dBA into a residential zone at night. A commercial emitter faces the same 62 dBA cap into industrial and commercial zones and the same 55/45 dBA day/night caps into a residential zone. An industrial emitter gets the widest allowance: 70 dBA into another industrial zone, 66 dBA into a commercial zone, and 61 dBA day / 51 dBA night into a residential zone. Subsection (a) makes it unlawful to emit noise beyond one's own property boundary in excess of whichever limit applies, and subsection (b)(4) treats a nonconforming use as belonging to the zone matching its actual use, not its zoning designation.

'Daytime hours' are defined elsewhere in the article, Sec. 18-73, as 7:00 a.m. to 10:00 p.m. Monday through Saturday and 9:00 a.m. to 9:00 p.m. on Sundays and holidays, with all other hours counted as nighttime. The city's health director measures fixed sources and the police chief measures mobile sources, using an ANSI S1.4-1971-compliant sound-level meter placed at least four feet above ground, about one foot inside the receiving property line, per Sec. 18-74. Where background noise from unregulated sources already exceeds these standards, Sec. 18-76 treats a source as excessive only if it adds five decibels above that background, and no source may exceed 80 decibels at any time regardless of ambient level. Violations of this decibel table are punishable under Sec. 18-82 by a fine up to the maximum authorized by state statute or city code per occurrence, with each day of a continuing violation counted separately.