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Disinfecting Your Well

If your water sample shows bacteria in your well, a good first step in trying to solve the problem is to disinfect your well. Disinfecting a well will kill bacteria that are present in your well and in the plumbing of your home. After disinfecting your well we recommend that you take three samples a week apart to see if the problem has been solved. It is important to keep boiling your water for one minute at a rolling boil until you know your water is safe to drink.

Disinfecting Your Well Instructions

  1. Mix Household Bleach (5% Available Chlorine) with water and pour directly into your well. The amount of bleach required depends on your type of well and the depth of the water in your well:
    • Dug Well 3 feet (40cm) diameter = 1.1 litre (1qrt) for every 5 feet (1.5 metre) water depth
    • Drilled Well 6 inches (15cm) = Diameter 5 ounces (150ml) for every 25 feet (7.5 metre) of water depth
  2. Drain water heater and remove or bypass carbon filters.
  3. Open all taps one at a time and let water run.
  4. Turn off taps when a bleach odour is noticed and let stand for 12 hours.
  5. Drain the water system to remove all chlorinated (bleach) water. Avoid draining this water into the septic tank, use a garden hose attached to an outside faucet.
  6. Resample your well water 48 hours later. If satisfactory, take 2 more samples 1 week apart to ensure water remains satisfactory.
  7. Sample your well water on a regular basis.

Bringing a Private Well back into Service Following a Flood