Iron County, UT Noise Ordinances: Decibel Limits (2026)

Section 17.33.030 sets development standards for utility-scale solar power plants sited under the Table of Uses at Section 17.16.030, and subsection (B)(5) is the only decibel standard in the Iron County Code that varies by both zone and time of day. It limits operating noise to fifty dBA measured at the property line of any neighboring residentially-zoned lot, forty-five dBA measured at an existing neighboring residence specifically between nine p.m. and seven a.m., and sixty dBA measured at the project's own boundary lines, with adequate setbacks required to meet each limit.

A property owner who would otherwise be protected can voluntarily accept a higher noise level only through a written, recorded agreement that the planning commission reviews and must find acceptable before it takes effect. By contrast, the county's other energy-facility noise standards are flat, not time-of-day based: commercial wind energy systems are capped at fifty dB at the project boundary under Section 17.34.040(B)(5), and geothermal power plants are capped at sixty-five dBA at the property line or fifty dBA at the nearest inhabitable building under Section 17.35.030(F).

None of these apply to ordinary residential noise, such as barking dogs or loud parties; the Iron County Code has no equivalent numeric limit for those.