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

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

Key Facts

Pre-1980 units
55 dB(A) exterior limit
Post-1980 units
50 dB(A) exterior limit
Applies to
Unincorporated areas only
Measured
Per § 6.60.030 method

Summary

Unincorporated Alameda County caps residential air conditioning and refrigeration equipment noise at 55 dB(A) for units installed before July 1980, and 50 dB(A) for newer units.

City-specific rules exist: Oakland, Livermore, Fremont, Berkeley, and San Leandro have their own hvac & mechanical noise rules that differ from Alameda County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

Notwithstanding the provisions of Section 6.60.040, where the intruding noise source, as measured pursuant to Section 6.60.030, is a residential air conditioning or refrigeration system or associated equipment installed prior to July 1, 1980, the exterior noise level shall not exceed fifty-five (55) dB(A). The exterior noise level shall not exceed fifty (50) dB(A) for such equipment installed after July 1, 1980.D."Plainly audible" means any sound that can be detected by a person using his or her unaided hearing faculties. As an example, if the sound source under investigation is a portable or personal vehicular sound amplification or reproduction device, the enforcement officer need not determine the title of a song, specific words, or the artist performing the song. The detection of the rhythmic base component of the music is sufficient to constitute a plainly audible sound.E.The restrictions contained in Section 6.60.050(B)(1), (2) and (3) shall not apply to:1.Activities which are governed by conditional use permits or other permits issued by the county, if those permits expressly regulate or control the amount of noise or sound which may be generated by the activities which are governed by the permit;2.Unincorporated areas of the county within the east county area plan; or3.Unincorporated areas of the county outside the urban growth boundary, as defined by "Measure D" ("Save Agricultural and Open Space Lands Initiative of 2000").

Source: Alameda County Code Ch. 6.60 NoiseView official code

Full Breakdown

The county's noise chapter sets a specific exterior noise ceiling for residential air conditioning or refrigeration equipment that overrides the general exterior noise tables: 55 dB(A) for equipment installed before July 1, 1980, tightening to 50 dB(A) for equipment installed after that date, measured per the chapter's standard noise-measurement method. This is a county rule for unincorporated territory only, Castro Valley, San Lorenzo, Ashland, Cherryland and similar communities, and does not apply inside Oakland, Berkeley, Fremont, Hayward, San Leandro or any other incorporated Alameda County city, each of which regulates HVAC noise under its own code.

Violations & Fines

Enforced by the county director of environmental health; exceeding the applicable dB(A) limit is a noise disturbance violation, generally an infraction.

Frequently Asked Questions

Why do older AC units get a higher limit?
The county grandfathered equipment installed before July 1, 1980 at 55 dB(A); anything installed after that date must meet the stricter 50 dB(A) limit.
Does this cover a unit in Castro Valley?
Yes. Castro Valley is unincorporated and governed directly by this county chapter, since it has no municipal government of its own.

Sources & Official References

Other rules in Alameda County

All Alameda County rules

California rules heatmap·Compare Alameda County to another location·View the California noise from specific sources overview

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