California Code, Health and Safety Code - HSC § 79160

(a) The city or county shall notify the department of the planned removal or remedial action. Upon receiving this notification, the department shall make a reasonable effort to notify any person identified by the department as a potentially responsible party for the site. If a potentially responsible party is taking the removal or remedial action properly and in a timely fashion, or if a potentially responsible party will commence the action within 60 days of this notification, the city or county may not initiate a removal or remedial action pursuant to this article.

(b) If a potentially responsible party for the site has not taken the action specified in subdivision (a), the city or county shall submit the estimated cost of the removal or remedial action to the department, which shall, within 30 days after receiving the estimate, approve or disapprove the reasonableness of the cost estimate. If the department disagrees with the cost estimate, the city or county and the department shall, within 30 days, attempt to enter into an agreement concerning the cost estimate.

(c) The city or county shall demonstrate to the department that it has sufficient funds to carry out the approved removal or remedial action without taking into account any costs of the action that may be, or have been, paid by a potentially responsible party.