Hercules, CA Noise Ordinances: Decibel Limits (2026)
Key Facts
- Outdoor residential goal
- Ldn 60 dBA
- Council discretion cap
- Ldn 65 dBA at small decks
- Indoor cap, new units
- Ldn 45 dBA
- Bedroom instantaneous cap
- 50 dBA
- Other rooms instantaneous cap
- 55 dBA
- Railroad noise source outdoor
- 70 dBA Ldn
- Governing section
- § 13-31.300(11)
Summary
New residential projects in Hercules must be designed to keep outdoor noise at or below Ldn 60 dBA and indoor noise in new units at or below Ldn 45 dBA. The City Council can allow up to 65 dBA at small decks when mitigation can't reach 60, and bedrooms face an added 50 dBA instantaneous cap.
The maximum acceptable noise levels in residential areas is a Ldn of 60 dBA. This level shall guide the design and location of future development, and is a goal for the reduction of noise in existing development. ... Where the City determines that providing a Ldn of 60 dBA or lower cannot be achieved after the application of feasible mitigations, a Ldn of 65 dBA may be permitted at the small decks at the discretion of the City Council. Indoor noise level shall not exceed a Ldn of 45 dBA in new housing units. ... Noise levels in new residential development exposed to an exterior Ldn of 60 dBA or greater shall be limited to a maximum instantaneous noise level in bedrooms of 50 dBA. Maximum instantaneous noise levels in all other habitable rooms should not exceed 55 dBA.
Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 555, passed March 25, 2025).
Full Breakdown
300(11) governs noise as a performance standard applied when the City reviews development permits. For new residential projects, the maximum acceptable outdoor noise level is Ldn 60 dBA, applied where outdoor use matters most, such as backyards in single-family developments and recreation areas in multifamily projects; small decks on apartments and condos are evaluated case by case, and the City Council may permit Ldn 65 dBA there at its discretion if 60 dBA proves infeasible after feasible mitigation. Indoor noise in new housing units cannot exceed Ldn 45 dBA, and where the noise source is a railroad, the outdoor exposure criterion shifts to 70 dBA Ldn for future development.
Where exterior noise reaches Ldn 60 dBA or more, instantaneous noise inside bedrooms is capped at 50 dBA, and at 55 dBA in every other habitable room, based on site noise monitoring for things like truck passbys and train whistles. Nonresidential projects and construction activity face separate exterior standards tied to Table 6 and Table 7 of the General Plan's Noise Element. The City's noise contour map on file at City Hall screens which projects must submit an acoustical study before a permit is approved.
Violations & Fines
A residential project built without meeting these Ldn limits is a Zoning Ordinance violation. Section 1-4.01 makes Code violations misdemeanors punishable by up to $1,000 and six months in jail unless charged as an infraction, escalating from $100 to $500 for repeat offenses within a year, with each day of noncompliance counted separately, and the City can require retrofits as a permit condition.
Frequently Asked Questions
What is Hercules' outdoor noise limit for new homes?
Is there an indoor noise limit too?
How does the City decide if a project needs a noise study?
Sources & Official References
Other rules in Hercules
California rules heatmap·Compare Hercules to another location·View the California noise ordinances overview
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Decibel Limits in Nearby Cities
How other cities in Contra Costa County handle decibel limits.