Unused or abandoned wells that have not been properly sealed can
provide a direct pathway for contaminants to enter the groundwater.
Contaminants from surface water, runoff, or sources, such as leaking sewers
or septic system drainfields, can enter the well through casings that have
deteriorated. An unused, unsealed well can potentially threaten water
quality for new wells. Unused wells also pose a safety hazard, especially
for children, pets, and livestock. It is illegal to dispose of wastes
in an unused well, and it will result in additional costs to clean the
well and possibly the groundwater before the well is sealed.
According to Minnesota law, a well must be sealed in any of the following situations:
1) The well is contaminated and cannot
be corrected.
2) The well has been improperly sealed
in the past.
3) The well poses a threat to the health
or safety of the public or to groundwater quality.
4) The well is not in use and does not
have a maintenance permit.
A water well is properly sealed when it is removed from service and
is completely filled with an approved grouting material by a licensed contractor.
YOU
MAY NOT SEAL YOUR OWN WELL! ONLY A LICENSED WATER WELL
CONTRACTOR MAY SEAL A WELL IN ACCORDANCE WITH MINNESOTA LAW.
1. Before a well can be sealed, any obstructions in the well - an
old pump, drop pipe, and any debris - must be removed. In some situations,
the well casing will have to be perforated - meaning that holes will have
to be punched through the casing. This helps ensure that both the
inside and the outside of the casing will be completely sealed when grout
is pumped into the well.
2. The well is sealed by completely filling it with grout, which is a special type of cement, concrete, or a clay known as bentonite. Filling the well casing with grout seals the well and helps protect aquifers from contamination. To ensure a complete and effective seal, free of voids, Minnesota regulations require that the grout be pumped into the well from the bottom upward. The licensed well contractor inserts a grout pipe (or tremie pipe) all the way down to the bottom of the well, and then pumps in the grout until it comes out the top.
3. After the well has been sealed, the licensed well contractor will send a Well and Boring Sealing Record to the property owner and to the Minnesota Department of Health. The property owner should keep this document with other important papers relating the the property.
To request an estimate for sealing an unused well on your property, see estimates on well sealings.