Use bleach to disinfect. Follow the instructions below for dug or drilled wells to determine how much bleach to use. If you know how much water is in your well, add bleach for that amount of water. If you don't know, add bleach amount for the depth of your well.
Make a solution of bleach water using the amounts of bleach and water shown below. Pour bleach in 10 gallons of water. Mix thoroughly. Splash on casing inside well. Seal top. Open faucet. Let run until you can smell bleach at the faucet. Close faucets. Let set overnight. Next day, open faucets. Let water run slowly until bleach smell is gone. Add bleach as follows:
Diameter of well... Add bleach
is 4 ft.... 3 cups per ft. of water
is 6 ft.... 6 cups per ft. of water
is 8 ft.... 12 cups per ft. water
If a well has a diameter of 6 feet, is 15 feet deep, and has 5 feet of water in it, add 30 cups of bleach. (6 cups x 5 feet of water).
Make a solution of bleach water using the amounts of bleach and water shown below. Remove the well seal. Pour the bleach solution into the well. Connect hose and spray inside of well casing for 15 minutes. Turn on water taps in house. Let it run until you can smell bleach at faucets. Turn water off. Let stand overnight. Next day, open faucets. Let water run slowly until bleach smell is gone.
To Make Bleach Solution
Find out how many gallons of water are in your well. For every 100 gallons of water in your well, add a mixture of: 3 cups bleach in 10 gallons of water.
If well diameter is... It holds this much water
6 inches... 1.5 gallons water per foot
8 inches... 2.5 gallons water per foot
10 inches... 4 gallons water per foot
12 inches... 6 gallons of water per foot
If well has... Add/mix
150 gal. water... 4.5 cups bleach in 15 gal. water
50 gal. water... 1.5 cups bleach in 5 gal. water
After you disinfect your well, have a sample of your tap water tested at your local health department. Before you drink the water, make sure 2 samples are rated satisfactory, to ensure it is safe and free of contamination.