In California, an idle well is a well that has not been used for two years or more and has not yet been properly plugged and abandoned (sealed and closed). Plugging and abandonment involves
permanently sealing the well with a cement plug to isolate the hydrocarbon-bearing formation from water sources and prevent leakage to the surface. If a well is not properly sealed and closed, it may provide a pathway for hydrocarbons or other contaminants to migrate into drinking water or to the surface. Improved reporting shows there are approximately 35,000 wells in California categorized as idle.
The Geologic Energy Management Division (CalGEM) revised its
idle well regulations in April 2019 to create far more stringent testing requirements that better protect public safety and the environment from the potential threats posed by idle wells. The regulations require idle wells to be tested and, if necessary, repaired, or permanently sealed and closed.
If an operator becomes insolvent or deserts their idle wells, responsibility for permanently sealing and closing these wells may fall to the State. Since 1977, CalGEM has plugged and abandoned about 1,400 wells at a cost of $29.5 million. To reduce the number of idle wells for which the State may become responsible, legislative and regulatory changes have been made to create incentives for operators to manage and eliminate their idle wells by entering into
Idle Well Management Plans (IWMPs). If an operator does not have an IWMP, the annual idle well fees the operator must pay for each of the operator’s idle wells have been increased to reflect the potential costs associated with those wells. The fees are deposited into the Hazardous and Idle-Deserted Well Abatement Fund to help fund the permanent sealing and closure of deserted wells.
In September 2024, Assembly Bill No. 1866 (AB 1866) passed into law, which amended sections 3206 and 3206.3 of the Public Resources Code. The annual idle well fees and idle well elimination requirements effective January 1, 2025 have increased. AB1866 alters the previsions of the Idle Well Management Plan (IWMP) requirements by removing the restriction of long-term idle wells and allowing for the management and elimination of all idle wells on the plan. The amended plan will require operators to consider specified factors when prioritizing idle wells for plugging and abandonment, in addition to increasing the minimum percentages of idle wells operators are required to eliminate each year. Any operator that does not file an IWMP must pay idle well fees annually which have been increased to reflect the potential costs associated with elimination of the idle wells.
Update
- Department of Conservation Idle Well Program Report, January 1, 2021-December 31, 2021 (PDF)
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Department of Conservation Idle Well Program Report, January 1, 2020-December 31, 2020 (PDF)
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Department of Conservation Idle Well Program Report, January 1, 2019-December 31, 2019 (PDF)
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Department of Conservation Idle Well Program Report, January 1, 2018−December 31, 2018
Inactive and deserted oil and gas wells that are not maintained can pose threats to groundwater and public safety. CalGEM has taken multiple steps to mitigate such potential hazards with ground-breaking legislation (Assembly Bill 2729, Williams, 2016) and development of rigorous regulations. There are incentives for operators to file Idle Well Management Plans for either plugging and abandoning long-term idle wells or returning them to production. Also, idle well fees have been increased to help encourage operators to address such wells in their inventories.
Idle Well Inventories
CalGEM manages two idle well inventories: annual fee inventory and IWMP inventory.
Annual Fee Inventory Includes all wells that met the definition of idle well in the prior calendar year. This inventory is used for the calculation of idle well fees.
IWMP Inventory includes all wells that met the definition of idle well on January 1 of the current calendar year. This inventory is used to establish the number of wells that must be eliminated by an operator in the current year if they elect to submit Idle Well Management Plans in lieu of pay an annual fee.
Idle Well Definitions
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Idle Well
"[A]ny well that for a period of 24 consecutive months has not either produced oil or natural gas, produced water to be used in production stimulation, or been used for enhanced oil recovery, reservoir pressure management, or injection. For the purpose of determining whether a well is an idle well, production or injection is subject to verification by the division.” (Pub. Resources Code, § 3008, subd. (d).)
A well
no longer meets the definition of idle well when:
“[A]n idle well continues to be an idle well until it has been properly abandoned in accordance with Section 3208 or it has been shown to the division’s satisfaction that, since the well became an idle well, the well has for a continuous six-month period either maintained production of oil or natural gas, maintained production of water used in production stimulation, or been used for enhanced oil recovery, reservoir pressure management, or injection. An idle well does not include an active observation well.” (Pub. Resources Code, § 3008, subd. (d).)
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Long-Term Idle Well (LTIW)
"[A]ny well that has been an idle well for eight or more years." (Pub. Resources Code, § 3008, subd. (e).)
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Idle Start Date
This is the date that the well meets the definition of idle well. It is the first day of the month following the 24th month of having not either produced or injected.
Example: If the last month of reported production on a well is January 2009, then its Idle Start Date is February 1, 2011.
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Active Observation Well
“[A] well being used for the sole purpose of gathering reservoir data, such as pressure or temperature in a reservoir being currently produced or injected by the operator. For a well to be an active observation well, the operator shall demonstrate to the division’s satisfaction that the well fulfills a need for gathering reservoir data, and the operator shall provide the division with a summary report of the type of data collected at least annually or as requested by the division.” (Pub. Resources Code, § 3008, subd. (c).)
Summary of 2025 Fees from the page linked above:
Annual Idle Well Fees (PRC 3206)
An operator is assessed idle well fees for each of the operator's idle wells that was idle at any time in the prior calendar year.
Idle well fees are calculated as follows:
| Years Idle | Current Fee ($) | New Fee ($) |
| 0-2.99 | $0 | $1,000 |
| 3-7.99 | $150 | $2,500 |
| 8-14.99 | $300 | $5,000 |
| 15-19.99 | $750 | $12,500 |
| 20+ | $1,500 | $22,500 |
Late penalties and accruing monthly interest: If an operator fails to pay their annual idle well fees by May 1, CalGEM will assess a 10% penalty and one and one-half percent (1.5%) non-compounding interest on the unpaid balance until paid in full. Any payments made will first be allocated to the owed penalties and interest. Any remaining funds will then be allocated to the outstanding fee balance. If the outstanding balance is not paid in full within two months of the due date, CalGEM may refer the operator to the State Controller's Office (SCO). Until the outstanding balance is paid in full, CalGEM and/or SCO will continue to assess interest at one and one-half percent (1.5%) per month until paid in full. (Pub. Resources Code, § 3420, subd. (b) and (d).)
Idle Well Fee Invoices: Digital copies of all invoices may be requested by emailing CalGEMIdleWells@conservation.ca.gov. When submitting a request, please include the operator code and invoice year in the email subject.
Idle Well Management Plans (IWMP)(PRC 3206)
An operator may file an IWMP in lieu of paying idle well fees no later than May 1 of each year. An IWMP filed after May 1 will not be accepted and the operator will be required to pay the annual fee and any associated late payment penalties and accrued interest. By filing an IWMP, the operator is committing to eliminating a specific number of idle wells per year. The IWMP and any revisions must be approved by CalGEM. The IWMP may cover a period up to 8 years and is subject to annual review by CalGEM. The required rate of elimination for an IWMP is based on the operator's idle well inventory as of January 1 of the current calendar year.
Effective January 1, 2025, the required annual percentage of all idle wells required to be eliminated is:
| State-Wide Idle Well Count | CY 2025-2027 | CY 2028-2029 | CY 2030 |
| 0-250 | 5% | 6% | 8% |
| 251-1,250 | 6% | 8% | 10% |
| 1,251-3,000 | 7% | 10% | 15% |
| 3,001+ | 15% | 18% | 20% |
An operator who fails to comply with their IWMP will have their IWMP cancelled and must immediately pay their idle well fees required under paragraph (1) of PRC section 3206. The operator may not propose a new IWMP for the following two years after the year that CalGEM determined that the operator failed to comply with their IWMP. In addition, the operator will only be able to propose a new IWMP after two years if the operator has paid all required idle well fees and any associated late payment penalties and accrued interest. (Pub. Resources Code, § 3206, subd. (a)(2)(H).) An operator whose IWMP or IWMP amendment has been either not approved or cancelled may appeal to the Department of Conservation (Department) pursuant to Article 6 (commencing with PRC § 3350).
