Cal. Pub. Res. Code § 3224.5

(a) After making a determination, based upon a site inspection, that a well poses a risk to life, health, property, or natural resources, the supervisor may order an operator, owner, or property owner to secure a site, based on a site inspection, if both of the following conditions apply to that site:
1. (1) The well does not comply with the regulations implementing this chapter.
2. (2) The well poses a risk to life, health, property, or natural resources.
(b)
1. (1) The order to secure the well shall require the posting of the site with signs. The order shall also require that the well be enclosed with a fence.
2. (2) If fencing is ordered, the fence shall be maintained at the well to prevent unauthorized persons from gaining access to the well.
3. (3) The signs shall be maintained and shall meet all of the following requirements:
  1. (A) Be bilingual, appropriate to the local area.
  2. (B) Have lettering that is legible from a distance of at least 25 feet.
  3. (C) Read: “Caution: Hazardous Well, Unauthorized Persons Keep Out” and shall have the name and telephone number of the division contact that ordered the posting.
  4. (D) Be visible from the surrounding area and posted at each route of entry into the site, including those routes that are likely to be used by unauthorized persons, at access roads leading to the well, and facing navigable waterways where appropriate.
  5. (E) Be of a material able to withstand the elements.
(c) An order of the supervisor to secure the site under subdivision (a) may be appealed by the owner of the property pursuant to Article 6 (commencing with Section 3350), except that in the case of an emergency a stay of the supervisor’s order shall not accompany the appeal.
(d) Within five days after service of an order pursuant to this section, or, if there has been an appeal from the order to the director, within five days after service of the decision of the director, or, if a review has been taken of the order of the director, within five days after affirmance of the order, the operator, owner, or property owner shall complete the work ordered. If the work is not completed within that time, the supervisor may appoint necessary agents to enter the premises and perform the work. If the supervisor determines that an emergency exists, the supervisor may secure and post the site as necessary to protect life, health, property, or natural resources pursuant to subdivision (b) of Section 3226. If the division undertakes work to secure a site pursuant to this section, an accurate account of the expenditures shall be kept and any amount expended shall constitute a lien pursuant to Section 3423 against real or personal property of the operator, owner, or property owner ordered to do the work. The division’s accounting of actual costs to perform work ordered shall be served by personal service or certified mail. For purposes of Section 3420, charges pursuant to this section for actual costs to perform work ordered are delinquent if not paid within 30 days after service of the accounting of costs.
(e) The remedies and penalties specified in this section are in addition to, and do not affect, any other remedies, enforcement actions, requirements, or penalties otherwise authorized by law.