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Short-Term Rentals

Castro Valley's Short-Term Rentals: The Rules That Matter

By CityRuleLookup Editorial Team

Every city handles short-term rentals a little differently. In Castro Valley, California, there are 2 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Occupancy Limits

Castro Valley STRs have no dedicated occupancy cap, but the unit must comply with California Building Code occupancy standards and Alameda County zoning use limits for the underlying single-family or multi-family district.

Key details: Code Reference: Cal. Bldg. Code §R310 / Alameda Ch. 6.65. Min Bedroom: 70 sq ft for 1 occupant. Per Additional: +50 sq ft each. HOA Override: Common in Castro Valley CC&Rs.

Overcrowding violations can be cited by Code Enforcement under §6.65.030 (real property nuisance) or by the Building Department under the CBC. Repeated guest-related disturbances may also trigger Chapter 6.60 noise actions.

Permit Requirements

Castro Valley STRs operate under Alameda County rules. There is no dedicated STR ordinance, but Chapter 6.64 (Rental Housing Registry) requires registration of rental units in the unincorporated area, and operators must obtain a Transient Occupancy Tax certificate before listing.

Key details: Registry Chapter: Alameda County Code Ch. 6.64. TOT Rate: 10% (Chapter 3.12). Stay Threshold: 30 days = transient. ADU Limit: ADUs cannot be rented <30 days.

Operating an unregistered STR is a code violation subject to administrative citation ($100-$500). Unremitted TOT becomes a tax lien plus interest and a 10% penalty. Renting an ADU short-term violates the zoning code and can trigger an NPO (Neighborhood Preservation Ordinance) order under Ch. 6.65.

The Bottom Line

Castro Valley's short-term rentals rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Castro Valley is broadly strict or permissive.

Keep in mind that Castro Valley can amend these rules at any council meeting. For the most current version of any rule mentioned here, check the specific ordinance page, where we track updates as they happen.