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Module 7 — Troubleshooting Water Well Problems
Improper Well Design and Construction
When designing a well, the licensed water well contractor must match the type of well
construction with the characteristics of the producing aquifer. Decisions must be made about:
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Perforated well casing/liner vs. well screen (see Figure 1, Perforated Well Liner
and Well Screen)
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Slot size of well screen
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Placement of well screen or perforated liner
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Size and amount of sand pack around the well screen (if required)
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Location of the pump in the well.
If poor choices are made, you may experience problems with sediment in your water or
reduced well yield. Provincial regulations require that a well must be completed to ensure
no damage will be incurred to the pumping system, plumbing or fixtures due to sediment in
the water. For more information on well design and construction, see Module 3 "Design and
Construction of Water Wells."
Incomplete Well Development
During drilling, mud and bore hole cuttings can partially plug the aquifer. This material
must be fully removed by the licensed water well contractor to allow water to freely enter the
well. This procedure is part of well development. If the well has not been fully developed, you
may experience problems with sediment in your water or low well yield.
Borehole Stability Problems
Borehole stability problems can result from damaged casing and screens, borehole
wall collapse, corrosion or excessive water velocities into the well. High water velocity can
cause formation particles, like sand, to flow into the well, causing eventual collapse of the
borehole wall.
It is essential that the proper materials be selected and installed to avoid such problems.
A combination of poor materials, improperly placed screens and a poor well seal make it
uneconomical to maintain and restore such a well. Often the most cost effective solution is to
drill a new well that is properly designed and constructed.
Figure 1 Perforated Well Liner and Well
Screen