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Cass County, MO Noise Ordinances: Decibel Limits (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Governing section
Cass County Code § 400.391(K)(2)
Daytime limit
50 dBA at property line
Nighttime limit
40 dBA at property line
Day-night average
45 dBA Ldn
Applies to
WECS-C wind turbine projects only
Noncompliance remedy
Forced shutdown until compliant

Summary

Cass County's Wind Energy Conversion Overlay District ordinance, § 400.391(K)(2), caps wind turbine noise at fifty dBA during daytime and forty dBA at night, measured at the nearest property line, with an overall day-night average not to exceed forty-five dBA Ldn.

These county ordinances apply to unincorporated areas of Cass County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

Noise Management. a. Measurement, Modeling, And Analysis. (1) A noise study shall be conducted to demonstrate that the system does not exceed an adjusted total day-night sound exposure (Ldn) of forty-five (45) dBA measured from the property line. ... b. ... Sound Level. The noise level caused by the operation of the project shall not exceed fifty (50) dBA during any daytime hours and forty (40) dBA during any nighttime hours, as measured at the nearest property line. The average adjusted total day-night sound exposure shall not exceed forty-five (45) dBA Ldn.

View official code

Full Breakdown

9-2005, IEC 61400 or ISO 9613 methodology. Once operating, the project's actual sound level cannot exceed fifty dBA during daytime hours or forty dBA during nighttime hours, measured at the nearest property line, with the day-night average still capped at forty-five dBA Ldn. 391 that carry the county's only measured noise ceiling. The Wind Energy Conversion Overlay District also requires WECS-C towers to be designed with at least three blades, an upwind rotor and a well-designed braking system to avoid disruptive low-frequency noise on top of the property-line dBA limits.

Violations & Fines

A complaint about noise from an operating WECS-C project goes to the Cass County Zoning Director; if the Director finds the complaint reasonable, the project owner has thirty days to commission a new professional noise study proving compliance with the dBA limits, under § 400.391(K)(2)(c). If the study shows the turbine is out of compliance, the Zoning Order requires the project 'shall be shut down until compliance can be demonstrated,' a stronger remedy than the Code's ordinary $1,000 general penalty at § 100.210.

Frequently Asked Questions

Does Cass County have a general decibel limit for noise complaints?
No. The county's general Peace Disturbance ordinance, § 205.670, prohibits unreasonably disturbing another person with 'loud noise' but does not set a decibel number. The only measured dBA limits in the Cass County Code apply specifically to commercial wind turbines under the Wind Energy Conversion Overlay District, § 400.391.
How loud can a wind turbine be at night in unincorporated Cass County?
No more than forty dBA measured at the nearest property line during nighttime hours, under § 400.391(K)(2)(b). Daytime noise is capped higher, at fifty dBA, and the day-night average sound exposure across a full day cannot exceed forty-five dBA Ldn under the same subsection.
What happens if a Cass County wind turbine exceeds the noise limit?
The Zoning Director can require the owner to commission a new professional noise study within thirty days of a reasonable complaint. If that study confirms the turbine exceeds the dBA limits in § 400.391(K)(2), the project must be shut down until the owner demonstrates compliance with the standard.

Sources & Official References

Other rules in Cass County

Parking Rules: Street Parking LimitsSome RestrictionsQuiet HoursSome RestrictionsParking Rules: RV & Boat ParkingLight RestrictionsVehicle NoiseSome RestrictionsParking Rules: Abandoned VehiclesSome RestrictionsParking Rules: Snow Removal Parking RulesSome RestrictionsFence Regulations: Retaining WallsSome RestrictionsFence Regulations: Material RestrictionsSome Restrictions

All Cass County rules

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