Geological Survey Program
Wellhead Protection Section
Monitoring wells are constructed to obtain site-specific water quality, contaminant movement or hydrologic data from proposed or existing sites that may impact groundwater quality. This requires their construction to be different from other types of wells. The majority of the other types of wells in Missouri use what is referred to as open-hole construction. Open hole construction fully exposes rock formations in the borehole of the well, below the well’s casing.
Monitoring wells constructed in Missouri use a full-length construction. In most cases, this means a screen in the shape of a pipe is connected to a solid-walled pipe, called a riser, both of which are installed in the open borehole. The screen is then surrounded by a filter material and the riser is sealed in place using one of several forms of sodium bentonite, or a cement and bentonite mixture.
Missouri sets the minimum construction standards for many types of monitoring wells. Lysimeters, injection and extraction wells, direct push or small diameter wells, soil vapor probes and piezometer wells are all examples of monitoring wells regulated under the Missouri Well Construction Rules.
All monitoring wells at least 10 feet deep and left in place more than 30 days must be reported. All monitoring wells at least 10 feet deep must be properly plugged and reported regardless of the length of time the wells were in service. Monitoring wells less than 10 feet deep are exempt from reporting rules or construction standards. However, as with all monitoring wells, those less than 10 feet deep must be plugged when their use is no longer required.
We offer a number of services that may be helpful in working with monitoring wells in Missouri. These services include:
Well Information Reports – Our database includes information on water wells drilled after The Water Well Drillers Act, sections 256.600 - 256.640 RSMo became effective in August 1985. This database includes all monitoring wells, heat pump wells and test holes installed after January 1994. When given a location in latitude and longitude, we can provide a detailed list of the wells within a desired radius. This radius can range from one-quarter mile to six miles - in quarter-mile increments. We can also provide the same information specific to a single section within a given township and range or all the wells within a given township and range. Submit a request to the Department of Natural Resources' Wellhead Protection Program.
Technical Assistance – We can provide technical assistance to industry members and information to the general public concerning the construction, certification, registration and the proper abandonment of monitoring wells within Missouri.
Variance Requests – If conditions at the site do not allow for the minimum construction standards under the Missouri Well Construction Rules to be met, the contractor can request a variance from a particular specification. This may involve increasing or augmenting the construction requirements for the well in other areas so as to ensure protection of the groundwater. Variance requests can be submitted by using the Variance Request Form or in case of an emergency situation by calling our office directly.
Permitting – A monitoring well contractor’s permit is required to construct, repair or properly plug a monitoring well in Missouri. A restricted monitoring well contractor’s permit is required for environmental or engineering entities to contract these activities or to act as the primary contractor on-site supervisor. Please contact our office for a list of contractors in your area or for information about acquiring a permit.