Step 1
Remove the well cap or protective wires, if present.
Step 2
Measure the correct amount of chlorine, which will depend on the size of your well. Roughly a gallon of household bleach or 1/8-cup chlorine is enough for a small to medium well. For a more exact estimate, calculate the volume of water in your well. Use 1 gallon of 5.25 percent chlorine bleach for 5,000 gallons of water.
Step 3
Use a garden hose to run water into your well, mixing thoroughly and cleaning the sides. Let the chlorinated water circulate throughout the water system.
Step 4
Allow the chlorine to remain in the well and pipes overnight, or for four to eight hours. This allows more time for all bacteria to be killed. Try not to use any water during this time. Never drink chlorinated water.
Step 5
Flush out the chlorine the next day. Run outside faucets for four to five hours until you don't smell any more chlorine. It's best to run the water into a ditch or drain. Don't run the chlorinated water onto fields or into streams where it can kill fish and animals. You can use chlorine testing strips to determine when the water is safe.
Step 6
Wait a few days before testing your well for bacteria. If there's any chlorine left in the water, this negates the test. Consider installing a permanent disinfection system if there are still bacteria present.