| Missouri Department of Natural Resources

03/22/2022
PUB3035

Geological Survey Program

fact sheet

Missouri Geological Survey

Director: Carey Bridges, RG

Background

When installing new or extending existing public water supply distribution lines, public water suppliers often disconnect homes and businesses from existing sources, often domestic wells, which are left unused and abandoned. If unused wells remain open, they pose a significant threat to the state’s groundwater resources by providing a direct pathway for surface and subsurface contaminants to enter drinking water aquifers. This is especially true for wells constructed prior to the implementation of well construction rules.

The Water Well Drillers’ Act, sections 256.600 to 256.640, RSMo, governs the well drilling industry and includes requirements for constructing and plugging wells. Section 256.628, RSMo, requires specific actions for both public water suppliers and well owners regarding wells disconnected and/or identified as abandoned prior to making the connection. These requirements are only applicable when a public water supply is connecting someone who is using a domestic well.

Requirements

Public water suppliers are required to inform well owner(s) of their obligation to plug any abandoned wells. Per section 256.603(1), RSMo, “… a well shall be deemed abandoned which is in such a state of disrepair that continued use for the purpose of thermal recovery or obtaining groundwater is impractical and which has not been in use for a period of two years or more.”

Public water suppliers may not connect any person to the public water system until that person submits to the public water supply accurate information regarding the location of any wells and attests that:

Known abandoned wells on the property have been plugged; or
There are no known abandoned wells on the property; or
Existing wells will remain in use and will be properly plugged when no longer used; or
Any abandoned wells will be plugged within 90 days.

Information regarding the location of wells and their status must be submitted to the public water supply using Public Water Supply Notification MO 780-1427. The public water supplier shall then submit a copy of the form to the Missouri Department of Natural Resources’ Well Installation section. It is the responsibility of the Well Installation section to follow up and inspect any documented abandoned wells to ensure they are plugged pursuant to the requirements in 10 CSR 23-3.110, Plugging of Water Wells. Wells may be plugged by the landowner or by a permitted well or pump installation contractor. More information about plugging and registration of abandoned wells can be found in Abandoned Wells: Locating, Plugging and Reporting - PUB2900.