Health & Saf. Code, § 17952

(a) In the event of nonenforcement of this part, or the building standards published in the California Building Standards Code, or the other rules and regulations promulgated pursuant to the provisions of this part, such provisions, building standards or other rules and regulations shall be enforced by the department in any city or county after the department has given written notice to the governing body of that city or county or fire protection district, as the case may be, of a violation of this part, those building standards, or the other rules or regulations promulgated pursuant to the provisions of this part and the city or county has failed to initiate proceedings to secure correction of the violation within 30 days of the date of that notice. The city or county or fire protection district may request a hearing before the department pursuant to Section 17930 within the 30 days to show cause for nonenforcement. Enforcement by the department shall not be initiated until the decision of the department, adverse to the city or county or fire protection district, is rendered.

(b) In the event of enforcement by the department pursuant to subdivision (a), the costs incurred by the department for such enforcement shall be borne by such city, or county, or city and county, or fire protection district. The department may assess fees to defray the costs of enforcement, thereby reducing the cost to be borne by the city, county, city and county, or fire protection district, but the department need not assess such fees and may not require the city, county, city and county, or fire protection district to assess fees to offset department costs.