The following is a state suggested formula for using bleach to disinfect a well:
1. Remove well cover. Pour the required amount of bleach into the well. SEE TABLE BELOW.
2. Run ALL faucets in the house, one at a time, until you smell the chlorine at the faucet.
This ensures that the whole system will be disinfected.
3. Connect a garden hose to an outside tap or an indoor tap with the correct thread fitting. Put the other end of the hose into the well, turn on the faucet, and from time to time move the hose so that the chlorinated water bathes the sidewalls of the well casing. Do this for at least six hours. Turn off tap and remove the hose from the well.
4. Replace the well cover.
5. DON’T USE THE WATER for at least twelve hours. Forty-eight hours in optimal.
6. Run the water to waste but NOT IN THE SEPTIC SYSTEM for several hours, or until the chlorine taste is dilute enough to be unobjectionable. The best way to run the water to waste is to use the garden hose mentioned above (item 3). Direct the hose into an area where the chlorinated water will not cause environmental damage or affect the water supply of others. For a typical well, this may take 3-4 hours.
NOTE: To avoid pump overheating and possible damage, turn off the water when flow is at a trickle and wait at least 15 minutes before turning on the pump again.
7. After a week of use, retest for bacteria.
8. In some cases, one chlorination treatment WILL NOT be sufficient. Repeat disinfection procedures as needed. You can also use calcium hypochlorite granules to provide a continuous release of chlorine in your well.
It is my opinion that you can never entirely disinfect a contaminated well. Think about it. You're using chlorine to attempt to eliminate every single individual bacteria. No. What you're doing is buying some time. The population will slowly rebuild. When you use chlorine you also release dangerous trihalomethanes into your water supply. These are very dangerous but can be removed with the proper filtration.
I recommend using hydrogen peroxide in place of chlorine. Both are oxidants. Hydrogen peroxide does not last as long in the well. It dissipates, converting to water and oxygen. Thus, you may have to repeat the treatment more often, but the byproducts are not hazardous. Apparently though if you have bromides in your well it can convert these to bromates which do have health impacts. As always, it is best to test before proceeding. The following instructions provide a thorough disinfection.
For more details on our products and services, please feel free to visit us at best whole house water filter, whole house water filtration, well water filter, water purification system, house water filter