Missouri Geological Survey fact sheet
Missouri Geological Survey Director: Joe Gillman, RG
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A test hole is a type of well drilled to collect geologic information. They are used for the exploration of minerals such as lead, coal, limestone or fireclay. Test holes are also used to gather stratigraphic or structural data that is not associated with an environmental characterization or remediation. Therefore, test holes do not include monitoring wells.

Test holes are temporary and may or may not have casing installed. They range in depth from 10 to more than 1,000 feet. Construction and plugging requirements are set in rule 10 CSR 23-6 to protect groundwater. Test hole plugging must be reported on a test hole plugging registration report. Test hole information is held confidential, by law, for 10 years and can be held confidential for an additional five years if requested by the responsible party.

The department offers a number of services that may be helpful regarding test holes in Missouri.

  • Well Information – Test hole records can be made publicly available once the period of confidentiality has passed.  
  • Technical Assistance – Technical assistance and information is available to industry members and the general public regarding test holes in Missouri. 
  • Variance Requests – A variance request must be submitted when the normal construction or plugging standards for a test hole cannot be met. This may involve increasing or augmenting the requirements to ensure protection of the groundwater. Emergency variance requests can be submitted electronically, by postal mail, or by calling our office directly.
  • Permitting – A test hole installation permit is required to install or plug test holes in Missouri. A restricted test hole installation permit is required for someone to contract these activities or to direct the installation or plugging. Use the Well Installation Online Services application to request permits.

Nothing in this document may be used to implement any enforcement action or levy any penalty unless promulgated by rule under chapter 536 or authorized by statute.


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