Downey, CA Noise from Specific Sources: HVAC & Mechanical Noise (2026)

Section 9504 sits in the zoning code's supplemental regulations and governs where and how mechanical equipment can be installed, not just how loud it can run. The core rule requires all air conditioning, mechanical roof, and utility equipment to be designed and located so it will not transmit noise or vibration to abutting properties, and to be screened from view from adjacent properties or public streets using landscape screens, walls, or other devices; screening design must also account for how the equipment looks from abutting multi-story buildings.

The City evaluates whether screening is adequate at the time of Site Plan Review. Beyond the general standard, § 9504 adds zone-specific placement limits: in residential zones, no swimming pool equipment, water heater, or air conditioning unit can sit in a street setback or within five feet of an interior property line. In the R-1 and R-2 zones specifically, roof-mounted equipment is banned outright, except for small wind energy systems, solar water heaters, solar power systems, or other passive solar energy systems, which are carved out because they serve an energy policy the City wants to encourage.

In commercial or industrial zones, swimming pool, air conditioning, or utility equipment such as transformer pads cannot sit in any portion of a required landscaped street setback or in a setback required next to a residential zone. Screening materials themselves must be architecturally compatible with the principal building and adjacent structures, subject to City Planner approval. The section cross-references § 4606 of the noise chapter for the decibel-level standards that apply once equipment is running, making § 9504 the siting and screening rule that works alongside, not instead of, the citywide noise limits.