​​​​Idle Well Program

​​​​​​​​​​​​​​​​​​​​​​​​​​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.

Idle Well, Cat Canyon Oil Field, Santa Barbara County


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

For Operators