How to Disinfect and Bleach a Well After Flooding

Because floods can cause contaminated water to get into wells, it is not safe to drink well water after a flood: the well must be disinfected before you can use water from it.

For this reason, it’s very important that you know how to disinfect a well yourself.

1. Wait until the floodwater recedes and power is restored.

2. Mix bleach (5.25% to 6%) with water. Use these amounts:

– 1 cup bleach in 5 gallons of clear water. – 2 cups to 1 quart of bleach in 10 gallons of clear water. – 2 quarts of bleach in 20 gallons of clear water.

3.  Pour the bleach mixture into the well.

If possible, use a hose to run the mixture down the inside of the well casing.  Aim to get the entire inside of the well casing wet with the mixture for at least 15 minutes.

4. Turn on all water taps and spigots in your home, sheds, garage, yard, etc.

Start with the taps which are furthest away from the well.  Keep the taps open until you can smell chlorine.

5. Turn the taps off.  Do not use the water for 8 hours.

6. Open all taps and spigots again.  Keep the taps open until you cannot smell chlorine anymore.