Cal. Civ. Code § PSC 113.0803

PSC 113.0803 Individual electric meters required for non-transient multi-dwelling unit residential buildings, mobile home parks and for commercial establishments.
(1) Each dwelling in a multi-dwelling unit residential building or mobile home park constructed after March 1, 1980, shall have installed a separate electric meter for each such dwelling unit. Dwelling unit means a structure or that part of a structure which is used or intended to be used as a home, residence or a sleeping place by one or more persons maintaining a common household and shall exclude transient multi-dwelling buildings and mobile home parks: for example, hotels, motels, campgrounds, hospitals, community-based residential facilities, residential care apartment complexes or similar facilities, nursing homes, college dormitories, fraternities, and sororities.
(2) Each tenant space in a commercial building constructed after March 1, 1980 shall have installed a separate electric meter.
(4) For the purpose of carrying out the provisions of subs. (1) to (2), individual unit metering will not be required:
(a) For a commercial building where the commercial unit space requirements are subject to alteration, as evidenced by temporary versus permanent type of wall construction separating the commercial unit spaces. Examples of temporary wall construction are partition walls which do not extend through the ceiling and walls which do not constitute a code-required fire separation.
(b) For electricity used in central heating, ventilating and air conditioning systems.
(bm) For a multi-dwelling unit residential building that meets one or more of the following conditions:
1. The electric equipment under tenant control meets established high energy efficiency standards consistent with standards used in a statewide energy efficiency programs under s. 196.374 (2) (a), Stats., federal energy efficiency standards, or other similar energy efficiency standards or programs and the average electric energy use per unit is projected to be less than half of the average monthly residential use per customer in Wisconsin based on the previous five-year average of U.S. energy information administration data, Wisconsin energy statistics, or similar state or federal government data. Onsite energy technologies that offset overall usage shall be factored into usage projections.
2. For a newly constructed building, the building design meets high energy efficiency standards. A building design meets high energy efficiency standards if the developer or owner of the building participates in programming for newly constructed buildings offered through a statewide energy efficiency program under s. 196.374 (2) (a), Stats., or a similar program.
3. The building is under contract with a local, state, or federal affordable housing program.
(5) For reasonable cause shown, the commission may grant waivers of this rule on a case-by-case basis. Applications for a waiver must be submitted to the commission in writing and set forth the facts or reasons the applicant believes justify a waiver.