California Code, Public Resources Code - PRC § 3724.5

To provide funds for the supervision of geothermal resource wells, the supervisor shall establish an annual well fee, and penalties for late payment, to be applied on an equal basis to all wells as provided under this section.

The annual well fee shall be imposed upon each producing, service, and idle well that existed at any time during the calendar year preceding the statewide fee-assessment date.  However, the annual well fee shall not be imposed on any temperature-gradient or observation well, irrespective of its depth, and any low-temperature well, including any well drilled for the purpose of filling a hot water spa or pool intended for human immersion, or any well for which the supervisor has approved suspension.

The annual well fee shall be established so that the sum of the annual well fees plus the estimated sum of those well permit fees provided in Sections 3724 and 3724.1 and pursuant to any regulation adopted under Section 3724.35 are equal to the appropriation for the supervision of geothermal resource wells as provided in the Governor's Budget.  The establishment of the annual well fee shall take into account any budget adjustments for actual expenditures in the current and prior fiscal years.  Any budget change proposal for support of the provisions of this chapter shall be submitted by the supervisor to geothermal operators for review and comment.  A system for determining the fee and penalties and administering the fee and penalty collection shall be adopted by the supervisor by regulation after public hearing.