Norwalk, CA Data Centers & Crypto Mining: Data Center Noise Limits (2026)
Key Facts
- Code
- Muni Code Ch. 9.04, Art. III
- Residential ambient
- 55 dBA day / 45 night
- Other zones
- 65 dBA anytime presumed
- Violation trigger
- Ambient plus five decibels
- Measured at
- Property line, three readings averaged
Summary
Norwalk sets no fixed decibel cap for industry. Municipal Code Section 9.04.120 presumes ambient levels of 55 dBA daytime and 45 dBA night in residential zones, 60 dBA commercial, 65 dBA elsewhere. Exceeding ambient by more than 5 decibels at a residential property line is a violation.
An average noise level reading measured pursuant to Section 9.04.130 which exceeds the ambient noise level at the property line of any residential land (or if a condominium or apartment house, within any adjoining apartment) by more than five decibels shall be deemed to be prima facie evidence of a violation of the provisions of this article.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4609620; v5 updated 2025-12-16).
Full Breakdown
Norwalk's noise ordinance is Title 9, Chapter 9.04, Article III. Section 9.04.120 presumes ambient noise at 45 dBA night and 55 dBA day in residential zones, 60 dBA anytime in commercial zones, and 65 dBA anytime in all other zones, including M-1 and M-2. Day runs 7:00 a.m. to 10:00 p.m. and night runs 10:00 p.m. to 7:00 a.m. Section 9.04.140(B) makes a reading that exceeds the ambient level at a residential property line by more than five decibels prima facie evidence of a violation. Section 9.04.130 requires three readings at two-minute intervals, averaged, taken at the property line.
Violations & Fines
Noise exceeding the ambient level by more than five decibels at a residential property line is prima facie evidence of a Chapter 9.04 violation, enforced by the City through citations and abatement.
Frequently Asked Questions
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Sources & Official References
Other rules in Norwalk
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