California Code, Government Code - GOV § 66005

(a) When a local agency imposes any fee or exaction as a condition of approval of a proposed development, as defined by Section 65927, or development project, those fees or exactions shall not exceed the estimated reasonable cost of providing the service or facility for which the fee or exaction is imposed.

(b) This section does not apply to fees or monetary exactions expressly authorized to be imposed under Sections 66475.1 and 66477.

(c) It is the intent of the Legislature in adding this section to codify existing constitutional and decisional law with respect to the imposition of development fees and monetary exactions on developments by local agencies. This section is declaratory of existing law and shall not be construed or interpreted as creating new law or as modifying or changing existing law.