Cal. Health & Safety Code § 17980

(a) If a building is constructed, altered, converted, or maintained in violation of any provision of, or in violation of any order or notice that gives a reasonable time to correct that violation issued by an enforcement agency pursuant to this part, the building standards published in the California Building Standards Code, municipal code, or other rules and regulations adopted pursuant to this part, or if a nuisance exists in a building or upon the lot on which it is situated, the enforcement agency shall, after 30 days’ notice to abate the nuisance or violation, or a notice to abate with a shorter period of time if deemed necessary by the enforcement agency to prevent or remedy an immediate threat to the health and safety of the occupants of the building, nearby residents, or the public, institute appropriate action or proceeding to prevent, restrain, correct, or abate the violation or nuisance. Notwithstanding the above, if a person has purchased and is in the process of diligently abating any violation at a residential property that had been foreclosed on or after January 1, 2008, an enforcement agency shall not commence an action or proceeding until at least 60 days after the person takes title to the property, unless a shorter period of time is deemed necessary by the enforcement agency, in its sole discretion, to prevent or remedy an immediate threat to the health and safety of the neighboring community, public, or occupants of the structure.
(b) If an entity releases a lien securing a deed of trust or mortgage on a property for which a notice of pendency of action, as defined in Section 405.2 of the Code of Civil Procedure, has been recorded against the property by an enforcement agency pursuant to subdivision (a) of Section 17985 of the Health and Safety Code or Section 405.7 or 405.20 of the Code of Civil Procedure, it shall notify in writing the enforcement agency that issued the order or notice within 30 days of releasing the lien.
(c)
1. (1) Whenever the enforcement agency has inspected or caused to be inspected a building and has determined that the building is a substandard building or a building described in Section 17920.10, the enforcement agency shall commence proceedings to abate the violation by repair, rehabilitation, vacation, or demolition of the building. The enforcement agency shall not require the vacating of a residential building unless it concurrently requires expeditious demolition or repair to comply with this part, the building standards published in the California Building Standards Code, or other rules and regulations adopted pursuant to this part. The owner shall have the choice of repairing or demolishing. However, if the owner chooses to repair, the enforcement agency shall require that the building be brought into compliance according to a reasonable and feasible schedule for expeditious repair. The enforcement agency may require vacation and demolition or may itself vacate the building, repair, demolish, or institute any other appropriate action or proceeding, if any of the following occurs:
  1. (A) The repair work is not done within the period required by the notice.
  2. (B) The owner does not make a timely choice of repair or demolition.
  3. (C) The owner selects an option that cannot be completed within a reasonable period of time, as determined by the enforcement agency, for any reason, including, but not limited to, an outstanding judicial or administrative order.
2. (2) In deciding whether to require vacation of the building or to repair as necessary, the enforcement agency shall give preference to the repair of the building whenever it is economically feasible to do so without having to repair more than 75 percent of the dwelling, as determined by the enforcement agency, and shall give full consideration to the needs for housing as expressed in the local jurisdiction’s housing element.
3. (3) If the enforcement agency determines that a building or portion thereof is substandard under this section based solely on the building or portion thereof being illegally occupied, the enforcement agency shall not commence court proceedings to abate the violation by repair if all of the following conditions are met:
  1. (A) The owner declares under penalty of perjury that the occupant is illegally occupying the building.
  2. (B) The owner filed and is diligently prosecuting an unlawful detainer action against the occupant or the occupant is being removed pursuant to Section 602 of the Penal Code.
  3. (C) The enforcement agency determines the building poses no risk to tenants, nearby residents, or the public.
(d)
1. (1) Notwithstanding subdivision (c) and notwithstanding local ordinances, tenants in a residential building shall be provided copies of any of the following:
  1. (A) The notice of a violation described in subdivision (a) that affects the health and safety of the occupants and that causes the building to be substandard pursuant to Section 17920.3 or in violation of Section 17920.10.
  2. (B) An order of the code enforcement agency issued after inspection of the premises declaring the dwelling to be in violation of a provision described in subdivision (a).
  3. (C) The enforcement agency’s decision to repair or demolish.
  4. (D) The issuance of a building or demolition permit following the abatement order of an enforcement agency.
2. (2) Each document provided pursuant to paragraph (1) shall be provided to each affected residential unit by the enforcement agency that issued the order or notice, in the manner prescribed by subdivision (a) of Section 17980.6.
(e) All notices issued by the enforcement agency to correct violations or to abate nuisances shall contain a provision notifying the owner that, in accordance with Sections 17274 and 24436.5 of the Revenue and Taxation Code, a tax deduction may not be allowed for interest, taxes, depreciation, or amortization paid or incurred in the taxable year.
(f) The enforcement agency may charge the owner of the building for its postage or mileage cost for sending or posting the notices required to be given by this section.
(g) If the enforcement agency determines that there is an infestation pursuant to paragraph (12) of subdivision (a) of Section 17920.3 or Section 116130, the enforcement agency’s abatement order shall require the abatement of any other conditions listed in Section 17920.3 that the enforcement agency determines to have caused the infestation.