Santa Cruz County — Noise Planning

Interior Noise and Sound Insulation

New residential structures must achieve no more than 45 dB Ldn in any habitable room. New nonresidential structures must achieve no more than 50 dB Ldn indoors. Construction must also comply with the applicable Title 24 requirements adopted by the County in Chapter 12.10; see the California Building Standards Code. § 13.15.090(A)

Special sound-insulating construction is required for new development in:

• A future highway or local-roadway noise contour of 60–65 dB Ldn or higher shown in General Plan Noise Element Figures 9-2a and 9-2b. § 13.15.090(A)(1)
• A future Watsonville Municipal Airport noise contour band of 60–65 dB Ldn or higher shown in Figure 9-4. § 13.15.090(A)(2)
• Other areas where a discretionary new-development application is known or determined to exceed the applicable General Plan Noise Element standards. The County may require an acoustical study to identify exterior exposure and needed insulation. § 13.15.090(A)(3)

Noise mitigation can affect building orientation, wall and window assemblies, ventilation, and outdoor-space design. Those choices may also intersect Santa Cruz County Development Standards, Santa Cruz County Design Review, and Santa Cruz County Overlay Districts, but Chapter 13.15 does not state their separate approval standards.

General Unlawful-Noise Rule

Except for a temporary construction operation, a use may not create noise beyond the project-site boundary that the Planning Commission finds nonconforming with the parameters in General Plan Noise Element Tables 9-2 and 9-3, at standard atmospheric pressure. § 13.15.050(A)

For enforcement and mitigation evaluation, noise is assessed at the receiving land use’s property line closest to the source, or where noise is highest. Ambient sound should be measured with the project source off when practical, or estimated elsewhere in the same noise sphere where project noise is inaudible. § 13.15.030(A)

The County may evaluate a barrier or property-line mitigation measure on the receptor side of that barrier. § 13.15.030(B)

Emergency Standby Generators

In residential zone districts in unincorporated Santa Cruz County, an emergency standby generator must use natural gas or propane. It may operate during a power outage and other temporary purposes defined in the chapter, but it may not operate between 10:00 p.m. and 7:00 a.m. unless needed for life support or other necessary medical needs, equipment, or medication. § 13.15.050(B)

The installation must meet the zone district’s property-line setbacks and the following manufacturer-noise-based setbacks. A reduction may be approved only with attenuation that limits exterior sound to 65 dBA at the nearest property line; the generator may never be closer than the applicable minimum zone-district setback. § 13.15.050(B)

Property-line placement remains important even if a generator meets the noise table. Chapter 13.15 does not provide the underlying residential district setbacks; verify those through the County’s applicable development standards. § 13.15.050(B)

District-by-District Applicability

CA — Commercial Agricultural

Chapter 13.15 excludes noise caused by normal and customary farming operations carried out on land that is both General Plan-designated and zoned CA for commercial agricultural use. § 13.15.040(H)

The chapter does not establish the CA district’s purpose, permitted uses, lot dimensions, building heights, coverage, or setbacks. Not found in source materials; verify the parcel’s designation and zoning with the jurisdiction.

Other zone districts

Chapter 13.15 does not establish district-specific permitted uses, dimensional standards, or a district-by-district noise threshold schedule for other zones. Its express residential-district rule concerns emergency standby generators, while commercial and industrial development is evaluated through the General Plan Noise Element tables and project-specific analysis. §§ 13.15.050(B), 13.15.070

Noise planning may affect site placement otherwise governed by Santa Cruz County Parking and setback or screening choices. However, parking ratios, district setbacks, and landscaping requirements are not found in source materials for this chapter.

Exemptions and Specialized Regulations

Chapter 13.15 does not apply to public-agency or utility construction, maintenance, and repair work considered necessary to protect public health, welfare, or safety. Examples include emergency utility restoration, road and sidewalk repairs, debris removal, sewer work, and traffic-signal repairs. § 13.15.040(G)

Normal and customary farming noise on qualifying CA land is also exempt. § 13.15.040(H)

Where another County Code provision supplies special noise regulations for a specific activity, that specialized regulation controls instead of Chapter 13.15. § 13.15.040(I) The chapter specifically identifies off-road motor vehicles, wineries, recycling facilities, wireless communication facilities, vacation rentals, and mining operations as separately regulated subjects. § 13.15.050(C)

For mining, the identified specialized standard limits noise at property boundaries to 60 dBA for a cumulative 15 minutes during any operating hour, subject to a potentially lower Planning Commission limit where a noise-related health, safety, or nuisance effect is demonstrated. § 16.54.050(C)(1)

Checklist

• Confirm the site is in unincorporated Santa Cruz County, not an incorporated city with its own code.
• Identify nearby noise sources and compare the project’s exposure with General Plan Noise Element Table 9-2. § 13.15.080
• For a commercial or industrial noise-generating project, determine whether an acoustic study is required under § 13.15.070(A).
• Evaluate whether the proposal increases noise at an existing noise-sensitive receptor by 5 dB Ldn at or below 60 dB Ldn, or 3 dB Ldn above 60 dB Ldn. § 13.15.070(A)(1)–(2)
• Design required mitigation and incorporate it into permit plans and conditions. §§ 13.15.070(A), 13.15.090(A)(3)
• Meet interior limits of 45 dB Ldn for residential habitable rooms or 50 dB Ldn for nonresidential structures. § 13.15.090(A)
• Check roadway and Watsonville Municipal Airport future noise contours for the 60–65 dB Ldn sound-insulation trigger. § 13.15.090(A)(1)–(2)
• If installing a residential emergency generator, verify fuel, operating-hours, noise rating, property-line setback, and any attenuation proposal. § 13.15.050(B)
• Confirm that all noise-related permit conditions can be met during operation. § 13.15.110(B)

Risks & Ambiguities

Plain-English Summary

If you are building in unincorporated Santa Cruz County, think about noise before finalizing the design: homes must be quiet inside, commercial and industrial projects may need an acoustic study, and a generator’s loudness determines how far it must sit from the property line. The County can attach mitigation conditions and enforce them through the development permit. §§ 13.15.050, 13.15.070, 13.15.090, 13.15.110

Source References

• Santa Cruz County Zoning Code § 13.15.010 — purpose and intent.
• Santa Cruz County Zoning Code § 13.15.030 — sound-level assessment and mitigation measurement.
• Santa Cruz County Zoning Code § 13.15.040(G)–(I) — public-safety, agricultural, and specialized-regulation exclusions.
• Santa Cruz County Zoning Code § 13.15.050 — unlawful noise, generators, and specialized noise regulations.
• Santa Cruz County Zoning Code § 13.15.070 — noise-generating commercial and industrial development.
• Santa Cruz County Zoning Code § 13.15.080 — exterior noise exposure.
• Santa Cruz County Zoning Code § 13.15.090 — interior noise and insulation.
• Santa Cruz County Zoning Code § 13.15.110 — administration and enforcement.
• Santa Cruz County Planning Code § 16.54.050(C)(1) — mining noise condition.
• California Building Standards Code