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Flooded Private Water Supply

What to do if your private water well has flooded

​​​​​​​What can cause my well water to be unsafe?

Your water might be contaminated (unsafe to use) with harmful bacteria or chemicals if:

  • your water well has flooded
  • surface floodwater got into the wellhead (the part of the well you can see above ground) and down into the well casing (material that supports the sides of the well)

Wells in pits or basements can also flood or be contaminated. When flooding happens, your well needs to be checked. Even if your well looks fine, bacteria and chemicals can still get in.

If my water well has flooded, can I use the water?

If your well has flooded, don’t use the water:

  • to drink, cook, or bathe. Use another safe water source (such as municipal truck-fill, bottled water, or a neighbour’s well that isn’t flooded) instead. If this isn’t possible, you must boil your water for 1 minute in a rolling boil to kill harmful bacteria before you use it. If your well is contaminated with chemicals, boiling won’t help to make the water safe.
  • until a licensed water-well contractor has checked your well and the floodwater has been flushed or purged from the casing, shock chlorinated, and tested.
    • What do I need to do to the well and pump?

      Floodwaters can carry waste (such as wood, rocks, metal) that can damage the well casing, electrical parts, and the pump.

      When the floodwaters have gone down, call a licensed water-well contractor to check your well system. The pump (including valves and gears) might need to be cleaned to remove any soil or sand.

      Don’t turn on the pump until a qualified electrician or a licensed water-well contractor checks the wiring system. You could damage the well and pump or even get electrocuted (harmed by electric shock).

      Do I need to have my well and plumbing disinfected?

      After flooding, your well and the whole plumbing system connected to it need to be shock chlorinated. This is a way to kill harmful bacteria.

      Do I need to have my well water tested?

      Before you use your well again, have the water tested for bacteria. You can get sample bottles and testing instructions from an Alberta Health Services (AHS) Environmental Public Health office. After testing, they will tell you if your water is safe to use. If you think your well has been contaminated with chemicals, contact AHS Environmental Public Health for testing.

      How do I protect my well from flooding again?

      When the flood is over and the well is safe again, check with a licensed water-well contractor or AHS Environmental Health to learn how to protect your well from future floods. This may include:

      • extending your well casing
      • installing a flood-proof cap with an extended vent
      • moving your well
      • upgrading pit wells​​

Current as of: February 18, 2021

Author: Environmental Public Health, Alberta Health Services