“Springtime flooding awareness” Part 3 – sump pumps & dewatering systems incomplete water evacuation

Is your property affected buy a dewatering system like a sump pump and well? If so, it is important to check the system for proper operation prior to rising water tables.

A typical system consists of a drainage drywell (drain-rock) surrounding a well case with a pump mounted in the well case activated by a float switch. When well fills with water to a pre-set height the float switch is activated turning on the pump which then pumps the water out of the well through plumbing lines to be safely discharged away from the protected structure.

To check the system for proper operation.

  1. Make sure the pump is plugged in to a proper GFI receptacle.
  2. Test that the power receptacle is supplying power by using a test light or an extension cord that is equipped with a power indicator light.
  3. Lift the float switch slowly until the pump is activated. Then let it back down slowly until the pump shuts off. Take notice of the position that the float must be in to activate the pump, this information is critical so that you can adjust the level of water that is acceptable to you before pump out is required.

Note: its is quite common that float switch’s fail, therefore it is important that this switch is tested regularly and especially in the spring before high water levels.

  • Check the well casing for proper function. The well casing should allow the water to run in without larger rocks and debris. In some cases, well casing (especially metal) can develop larger holes which can cause the well to fill up with debris which will limit the efficiency of the pump and in some cases stop the pump from working altogether.
  • Evacuation plumbing lines can be checked by filling the pump well and activating the pump. The drain plumbing is often buried and is hard to inspect without special aids like a camera snake. At best you will be able to determine if the line is blocked by pumping water through. If the well drops, it is a good indication that the line is flowing clear.
  • Finally, its important that the water being pumped out is being distributed beyond the immediate water table so that it does not cause re-saturation.

De watering systems like this should be plentiful and multiple pumps well systems should be employed so that during high water tables and extreme weather events the system is able to keep the water table well below the level that would allow water to exert hydraulic pressure on the slab floor or dirt level thereby keeping vapour pressure from permeating into the living space.


Mark J. Gotro


HYDRACLEAN Disaster Restoration Services Ltd.

Since 1988

24hrs every day of the year – 1-877-91FLOOD – 1-877-913-5663



Our advice is always free.

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