Cal. Pub. Res. Code § 43501

(a) A person owning or operating a solid waste landfill, as defined in Section 40195.1, shall do both of the following:
1. (1) Upon application to become an operator of a solid waste facility pursuant to Section 44001, certify to the board and the local enforcement agency that all of the following have been accomplished:
  1. (A) The owner or operator has prepared an initial estimate of closure and postclosure maintenance costs.
    1. (i) The board shall adopt regulations that provide for an increase in the initial closure and postclosure maintenance cost estimates to account for cost overruns due to unforeseeable circumstances, and to provide a reasonable contingency comparable to that which is built into cost estimates for other, similar public works projects.
    2. (ii) The board shall adopt regulations on or before January 1, 2008, that require closure and postclosure maintenance cost estimates to be based on reasonably foreseeable costs the state may incur if the state would have to assume responsibility for the closure and postclosure maintenance due to the failure of the owner or operator. Cost estimates shall include, but not be limited to, estimates in compliance with Sections 1770, 1773, and 1773.1 of the Labor Code, and the replacement and repair costs for longer lived items, including, but not limited to, repair of the environmental control systems.
  2. (B) The owner or operator has established a trust fund or equivalent financial arrangement acceptable to the board, as specified in Article 4 (commencing with Section 43600).
  3. (C) The amounts that the owner or operator will deposit annually in the trust fund or equivalent financial arrangement acceptable to the board will ensure adequate resources for closure and postclosure maintenance.
2. (2) Submit to the regional water board, the local enforcement agency, and the board a plan for the closure of the solid waste landfill and a plan for the postclosure maintenance of the solid waste landfill.
(b) Notwithstanding subparagraph (C) of paragraph (1) of subdivision (a) or any other provision of law, if the owner or operator is a county with a population of 200,000 or less, as determined by the 1990 decennial census, the county shall not be required to make annual deposits in excess of the amount required by the federal act or any other applicable federal law, or by any board-approved formula that meets the requirements of the federal act.
(c) If not in conflict with federal law or regulations, a county or city may, with regard to a solid waste landfill owned or operated by the county or city, base its estimate of closure and postclosure maintenance costs on the costs of employing county or city employees or persons under contract with the county or city in performing closure and postclosure maintenance. However, even if, to meet federal requirements, the cost estimate is based on the most expensive costs of closure and postclosure maintenance performed by a third party, the county or city may, to effect cost savings, employ county or city employees or employ persons under contract to actually perform closure operations or postclosure maintenance operations.