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Water Safety

Private Water Supply

​​What do I do if my well has flooded or might be contaminated?

If you have an untreated water well, do not drink the water if it:
  • has flooded (or rained very heavy)
  • might be contaminated
After the flood waters go down, you need to disinfect the well and test the water to make sure it is safe to use. If you think (or have been told) your water is not safe, use bottled, boiled, or distilled water to:
  • drink
  • cook
  • prepare any food
  • wash your hands
  • bathe or shower
  • brush your teeth

How can I make my private water supply safe?

If you think (or have been told) your water supply is contaminated with chemicals, the ways to disinfect it listed below might not make your water safe to drink. You need to get water from a safe source (e.g., bottled water).

Until your well is disinfected and tested, you need to treat your water with boiling, chlorination, or iodine crystals until it is safe to drink.

How do I disinfect my water with boiling?

You need to prepare the water ahead of time and cool it before you can use it.

  1. Put some water in a clean cooking container (e.g., pot). If the water is cloudy, strain it with a coffee filter.
  2. Bring the water to a rolling boil for at least 1 minute.
  3. Cool the water in the fridge overnight.

How do I disinfect my water with chlorination?

You can chlorinate your water using water purification tablets or bleach.

Water Purification Tablets

You can buy water purification tablets from most outdoor supply or camping stores. Follow the directions on the package.

Bleach

To chlorinate your water using bleach you will need these supplies:
  • 1 litre container
  • medicine dropper
  • unscented, household bleach (5.25 percent strength)

If your water is clear:

  1. Add 2 drops of bleach to 1 litre of water.
  2. Mix the water thoroughly and let it stand for 30 minutes. If there is a slight chlorine smell and the water looks clear, it is safe to drink.
If your water is cloudy:
  1. Add 4 drops bleach to 1 litre of water.
  2. Mix the water thoroughly and let it stand for 30 minutes. If there is no chlorine smell, add 4 more drops of bleach and let the water stand for another 30 minutes.

How do I disinfect my water with iodine crystals?

You can buy iodine crystals from most outdoor supply or camping stores. Do not use iodine for more than 3 weeks per summer (in controlled doses), as there is a risk of thyroid problems or iodine sensitivity. Do not drink water disinfected with iodine if you:
  • are pregnant
  • have a thyroid problem
  • are hypersensitive to iodine
To disinfect water with iodine, you will need these supplies:
  • 1 litre container
  • 30 mL clear glass bottle
  • storage container for water (after it is disinfected)
  • elemental iodine crystals
  1. Make an iodine solution. Put 4 to 8 grams of iodine crystals in the glass bottle. Fill the bottle with water and shake it. Let it settle. This solution can cause very bad problems if swallowed all at once. Keep the solution away from children.
  2. Put 1 litre of water in the storage container.
  3. Add 15 mL of the iodine solution (do not transfer solid crystals from the glass bottle to the water in the storage container).
  4. Let the water stand for 15 minutes.
  5. You can repeat these steps using the same iodine solution as long as there are iodine crystals still in the clear glass bottle.

If you have any questions about your water, call Environmental Public Health.

Current as of: March 8, 2018

Author: Environmental Public Health, Alberta Health Services