Bothell, WA Noise from Specific Sources: HVAC & Mechanical Noise (2026)

Bothell regulates outdoor mechanical equipment in BMC 12.14.070(E), part of the zoning section on setbacks that apply to specific buildings or uses. It covers pad-mounted heating, ventilation and air conditioning equipment such as heat pumps, air conditioning units and furnaces installed after October 16, 2010. Three rules apply. First, the equipment cannot sit in any front yard setback area. Second, it must be at least three feet from any adjacent property line or structure, and the code names fences as a structure for this purpose. Third, it must be screened from view of any public right-of-way with landscaping or fencing. The code says the screening should be installed so it can be readily removed for access, or placed at least three feet from the equipment. Portable generator use during emergencies is carved out of these requirements.

This provision governs where a unit goes, not how loud it runs. Sound from a compressor or fan that reaches a neighbor falls under Chapter 8.26 BMC. BMC 8.26.040 bars noise that exceeds the maximum permissible level in WAC 173-60-040, which the city adopts by reference. BMC 8.26.060(H) lists frequent, repetitive or continuous sounds emanating from any building, structure, apartment or condominium that unreasonably interfere with the peace, comfort and repose of property owners as a public nuisance. Rooftop equipment is handled differently: BMC 12.14.120(A) lets roof structures housing or screening ventilating fans, HVAC or similar equipment rise above the building height limit set by BMC 12.14.110. The three-foot clearance and the front yard ban therefore matter most for ground-level units beside houses, where the neighboring lot line is closest.