Module 9 — Plugging Abandoned Wells
77
Steps to Plugging a Well
Remove all pumping equipment from the well. Thoroughly flush out the well using a bailer
or air compressor.
Measure the total depth of the well, the diameter and the non-pumping water level. If
possible, compare these figures with the information on the original drilling report. Confirm
whether the well is open to its original depth.
Use these figures to decide which plugging material is appropriate and how much you will
need. A licensed water well contractor can help you decide. Whether or not the casing can
be successfully pulled out will also determine which material to use and what method is
appropriate for placing it into the well. If the casing cannot be removed, choose a slurry that
can be pumped under pressure into the well so that any space around the outside of the
casing will also get filled in.
Disinfect the well. Add enough chlorine to bring the water standing in the well to a
chlorine concentration of 200 mg/L. For every 450 L (100 gal.) of water in the well, add 2
L (0.4 gal.) of household bleach (5.25% chlorine). See Module 6 "Shock Chlorination—Well
Maintenance" to calculate how much water is in your well. Leave this chlorine in your well.
If possible, remove the well casing.
Place the plugging material into the well. It must be introduced at the bottom of the well
and placed progressively upwards to ground surface. The only exception to this rule is
when the plugging material being used is a bentonite pellet that has been designed and
manufactured for pouring into the well from the ground surface.
If the casing was not already removed, dig around it and cut it off a minimum of 0.5 m (20
in.) below the ground surface (see Figure 4, Cutting Off the Casing and Mounding the Clay).
Backfill and mound this portion of the hole with material appropriate for intended use of the
land (i.e., clay) (see Figure 4, Cutting Off the Casing and Mounding the Clay).
Use the worksheet at the end of this module to record the details of your well plugging.
Include the well owner name, legal land description, GPS location, total depth, casing
diameter, type and amount of plugging material used, date and method of placing material
into the well. Send a copy of this record to:
Alberta Environment
Groundwater Information Centre
11
th
Floor, Oxbridge Place, 9820-106 Street
Edmonton, Alberta T5K 2J6
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Figure 4 Cutting Off the Casing and
Mounding the Clay
Step 8
Step 9
By regulation, a well must be filled full
length with impervious material. That
material must be introduced into the well
at the bottom and be placed progressively
upward to ground surface.