Cal. CIV § 798.41

(a) Where a rental agreement, including a rental agreement specified in Section 798.17, does not specifically provide otherwise, the park management may elect to bill a homeowner separately for utility service fees and charges assessed by the utility for services provided to or for spaces in the park. Any separately billed utility fees and charges shall not be deemed to be included in the rent charged for those spaces under the rental agreement, and shall not be deemed to be rent or a rent increase for purposes of any ordinance, rule, regulation, or initiative measure adopted or enforced by any local governmental entity which establishes a maximum amount that a landlord may charge a tenant for rent, provided that at the time of the initial separate billing of any utility fees and charges the rent chargeable under the rental agreement or the base rent chargeable under the terms of a local rent control provision is simultaneously reduced by an amount equal to the fees and charges separately billed. The amount of this reduction shall be equal to the average amount charged to the park management for that utility service for that space during the 12 months immediately preceding notice of the commencement of the separate billing for that utility service.

Utility services to which this section applies are natural gas or liquid propane gas, electricity, water, cable television, garbage or refuse service, and sewer service.

(b) This section does not apply to rental agreements entered into prior to January 1, 1991, until extended or renewed on or after that date.

(c) Nothing in this section shall require rental agreements to provide for separate billing to homeowners of fees and charges specified in subdivision (a).

(d) Those fees and charges specified in subdivision (a) shall be separately stated on any monthly or other periodic billing to the homeowner. If the fee or charge has a limited duration or is amortized for a specified period, the expiration date shall be stated on the initial notice and each subsequent billing to the homeowner while the fee or charge is billed to the homeowner.