Monitoring Wells - PUB2898

Monitoring wells are used to collect groundwater information like depth to water, flow direction, and the presence of contaminants. The information gained can help protect Missouri’s aquifers. Missouri Well Construction Rule 10 CSR 23 chapter 5 outlines requirements for monitoring well installation and plugging. Many types of monitoring wells are addressed in rule, including lysimeters, injection and extraction wells, direct push or small diameter wells, soil vapor probes and piezometers.

Monitoring wells typically consist of 2-inch diameter PVC pipe and screen installed in a 6-inch diameter borehole to a desired depth. The screen interval is surrounded by a filter pack material, like sand, that allows water to flow into the well. The pipe, commonly called riser, is surrounded by bentonite or a cement and bentonite mixture to seal the space outside the pipe and inside the borehole wall. This prevents water and contaminants from flowing vertically along the well. 

The installation of monitoring wells must be reported to the department by submitting a monitoring well certification report. Temporary monitoring wells are exempt from installation reporting requirements, but must be plugged within 30 days of installation. Monitoring wells that are no longer in use must be plugged as indicated in the rules. All monitoring well plugging must be reported using a monitoring well plugging registration report. Monitoring wells less than 10 feet deep are exempt from the rules.

• Monitoring Well Certification Report MO 780-1415
• Nested Monitoring Well Certification Report MO 780-2169
• Monitoring Well/Test Hole/Soil and Geotechnical Boring Plugging Registration Report MO 780-2161

The department offers a number of services that may be helpful in working with monitoring wells in Missouri.

• Well Information – Our Well Installation Management System tool allows you to search our database for well records and permitted well and pump installation contractors. The database includes information on monitoring wells installed after January 1994. 
• Technical Assistance – We can provide technical assistance and information to industry members and the general public concerning the construction, certification, registration and the proper plugging of monitoring wells within Missouri. 
• Variance Requests – A Variance Request MO 780-1422 must be submitted when the normal construction standards for a well cannot be met. This may involve increasing or augmenting the construction requirements to ensure protection of the groundwater. Emergency variance requests can be submitted by calling our office directly.
• Permitting – A non-restricted monitoring well installation permit is required to construct, repair or properly plug a monitoring well in Missouri. A restricted monitoring well installation permit is required for someone to contract these activities or to direct the installation or plugging.