Water Wells - PUB2945

Nearly 3 million Missourians depend on water wells for their drinking water. Many also rely on water wells for irrigation and industrial supply. As such, there are several types of water wells: domestic (private residence), multiple family, non-community public water supply, community public water supply and high yield. The type of well needed is based on the number of service connections, the number of people served, geology of the site and the amount of water needed. The Water Well Drillers Act sections 256.000 to 256.640 RSMo, and the Missouri Well Construction Rules 10 CSR 23 define well types and establish well construction standards aimed to protect Missouri's groundwater. The rules are designed so contamination from the surface does not enter the subsurface from an improperly constructed well, or known contaminated water doesn’t spread to another aquifer. 

The quality and availability of groundwater in Missouri varies across the state. Some areas have abundant, high quality groundwater, while other areas have limited amounts of water or water that is mineralized, muddy or contaminated. Drilling areas with specific well construction requirements exist to help address this variability. Drill area information can be found using the Geosciences Technical Resource Assessment Tool, GeoSTRAT. Because of the variability of groundwater in Missouri, rules cannot guarantee water produced from a properly constructed well will be of usable quality. In certain instances, more casing and grout may be necessary to construct a well that will draw potable water. Experienced, permitted drillers or pump installers can help determine when more stringent construction would be necessary.

The department offers a number of services that may be helpful in determining where, how and what to look for when drilling a new well. 

• 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 water wells installed after October 1986. This and more information also is available within GeoSTRAT. Geologic Well Log Symbol Key and Descriptions - PUB2932 aid in understanding information contained on well logs. 
• Casing Point Request – A casing point request may be submitted by anyone seeking specific casing requirements in certain drilling areas. This is especially useful when planning to install a well in drill areas 8, 9 and 11.
• Variance Request – A variance request must be submitted when the normal construction standards for a well cannot be met. This may involve increasing or augmenting the construction requirements for the well to protect the groundwater. Emergency variance requests can be submitted by calling our office directly.
• Permitting – A non-restricted water well installation permit is required to construct or repair a water well in Missouri. A non-restricted pump installation permit is required to install or replace a pump in a water well. A non-restricted pump installation permit is also needed to install or repair the plumbing and electrical lines from the well to the point of entry in the structure. A restricted water well or pump installation permit is required for someone to contract these activities or to direct the installation. Landowners may install their own well or pump without a permit pursuant to the above mentioned law and rules. Use the Well Information Management System tool to request these permits.
• Technical Assistance – We are happy to provide technical assistance to the public and industry on water well and pump questions.
• Sensitive Area Maps – Well construction requirements are determined by geologic, hydrologic and environmental factors.