CA Health & Safety Code Section 17980.6

If any building is maintained in a manner that violates any provisions of this part, the building standards published in the State Building Standards Code relating to the provisions of this part, any other rule or regulation adopted pursuant to the provisions of this part, or any provision in a local ordinance that is similar to a provision in this part, and the violations are so extensive and of such a nature that the health and safety of residents or the public is substantially endangered, the enforcement agency may issue an order or notice to repair or abate pursuant to this part. Any order or notice pursuant to this subdivision shall be provided either by both posting a copy of the order or notice in a conspicuous place on the property and by first-class mail to each affected residential unit, or by posting a copy of the order or notice in a conspicuous place on the property and in a prominent place on each affected residential unit. The order or notice shall include, but is not limited to, all of the following:

(a)

The name, address, and telephone number of the agency that issued the notice or order.

(b)

The date, time, and location of any public hearing or proceeding concerning the order or notice.

(c)

Information that the lessor cannot retaliate against a lessee pursuant to Section 1942.5 of the Civil Code.