Frederick, MD Noise Ordinances: Decibel Limits (2026)

Section 15-21.2(a) states that no person may create or permit noise exceeding the levels in Table 1, which the ordinance says are 'the maximum levels permitted by state law.' Table 1 breaks limits down by receiving zoning district and time of day: industrial zones stay at 75 dBA both day and night; commercial zones allow 67 dBA in the day and 62 dBA at night; and residential zones allow 65 dBA in the day and 55 dBA at night. Zoning districts are defined for this purpose in § 15-21.1(j): 'Commercial' covers zones BO, B1, B3, DBO, and DB; 'Industrial' covers M1, M2, and MO; and 'Residential' covers R-0 through R-7, DR, and DR-B.

Readings must be taken with sound level meters meeting ANSI S1.4-1971 Type II specifications, measured at the property line of the receiving property or at a zoning district boundary, per § 15-21.5. A separate, more specific numeric exception applies to home air conditioning and heat pump equipment under § 15-21.3(b)(13): AC equipment is capped at 70 dBA and heat pump equipment at 75 dBA measured at the receiving residential property, both higher than the general 65/55 dBA residential ceiling in Table 1. Measuring a level above the applicable Table 1 figure is prima facie evidence of a violation under § 15-21.6(a).