Are utilities considered part of rent in California?

It depends on the lease. If the California lease bundles utilities into the monthly rent (one combined number, paid to the landlord), they are part of rent for purposes of the rent cap, the deposit cap, and rent increase notice. If the lease separates them (tenant pays the utility company directly, or pays a separate utility allowance to the landlord), they are usually NOT part of rent. California requires 30 days notice for rent increases of 10% or less and 90 days notice for increases above 10%. AB 1482 caps annual increases at the lower of 5% + local CPI or 10% flat, with exemptions for natural-person single-family owners and buildings under 15 years old. A landlord who shifts utilities from "included" to "tenant pays" mid-tenancy without proper notice is effectively raising rent and must comply with the rent increase notice rules. Some California jurisdictions also require RUBS (ratio utility billing system) or sub-metering disclosures before splitting utilities. The key question: does the change increase the tenant's net monthly out-of-pocket cost? If yes, treat it as a rent increase.

Source: Cal. Civ. Code 827(b)