Cal. Civ. Code § 770

  § 770. Grounds for the proceeding. 1. One-third or more of the tenants
occupying a dwelling located in the city of New York or the commissioner
of the department of the city of New York charged with enforcement of
the housing maintenance code of such city, or in the counties of Nassau,
Suffolk, Rockland and Westchester may maintain a special proceeding as
provided in this article, upon the ground that there exists in such
dwellings or in any part thereof a lack of heat or of running water or
of light or of electricity or of adequate sewage disposal facilities, or
any other condition dangerous to life, health or safety, which has
existed for five days, or an infestation by rodents, or any combination
of such conditions; or course of conduct by the owner or the owner's
agents of harassment, illegal eviction, continued deprivation of
services or other acts dangerous to life, health or safety, or the
issuance of an order to the owner of such dwelling by the commissioner
of such department of the city of New York pursuant to the alternative
enforcement program under section 27-2153 of the administrative code of
the city of New York, provided that such dwelling has not been
discharged from the program pursuant to such section and there has not
been a determination that the owner has substantially complied with such
order.
  2. If the proceeding is instituted by the commissioner of the
department of the city of New York charged with enforcement of the
housing maintenance code of such city, one-third or more of the tenants
may, at any time thereafter during the pendency of the proceeding or
after final judgment pursuant to section seven hundred seventy-six or
seven hundred seventy-seven of this article, petition for substitution
of themselves in place and stead of such commissioner of such
department. Such substitution shall be ordered by the court unless good
reason to the contrary shall be shown.