Shock Chlorination is a method of killing bacteria in a water well by adding chlorine bleach. This is the most common method homeowners will use to sanitize a well if it test positive for Coliform Bacteria or if there are other reasons to be concerned about bacteria or viruses.

 

Prior to Shock Chlorination

 

Before you Shock Chlorinate your well, take any precautionary steps to ensure you well does not become contaminated in the future. If your well is compromised, then shock chlorination will only be a temporary solution. It is best to solve the root cause of the issue if possible.

Here are some other steps you will need to take before shock chlorination.

 

• Check Filtration Equipment. Some water filters like RO (Reverse Osmosis) systems aren’t rated to handle high levels of Chlorine. Check with the manufacturer before running highly chlorinated water through any water filtration equipment. Some filters and water softeners will need to be bypassed.
• Have protective equipment. You want to avoid Bleach getting directly onto your skin and especially in your eyes. Make sure to have safety glasses and proper gloves to handle bleach.
• Avoid Ammonia. Do not mix Bleach with another cleaning chemical, especially ammonia. Mixing chemicals can create toxic gas.
• Ensure you have plain bleach. Do not use any bleach that is scented such as “fresh” or “lemon” scented.
• Have water for clean-up. Keep at least a 5 Gallon bucket of clean water nearby to help with cleaning.
• Have a plan for the run-off. You will want to use a hose to run the chlorinated water away from any septic system or landscaping. The chlorinated water may damage your septic system and will kill any grass or plants. If you have a plain gravel area or an area out of view, this is where you will want your hose running to.
• Remove Aerators: Shock Chlorination may break off scaling and other deposits. These can clog aerators and other filters if they are not removed prior to flushing.

 

Shock Chlorination Step-by-Step

 

1. Determine the Depth of Water in your well and Measure your Well Casing.

If you do not know the depth of your water, you can subtract the total depth of the well from the water table. This information is likely in your well log if you have one.

 

2. Measure out the correct amount of Chlorine Bleach.

 The amount of Chlorine you will use is based on your Depth of Water and your Well Casing. Consult the table below.

If you are using HTH (High-Test Hypochlorite) instead of household bleach, consult this table instead.

 

 

3. Dilute the Chlorine with Water.

The Bleach you are using will be diluted with approximately 4 gallons of water. This just gives you more volume of disinfectant for the shock chlorination.

 

4. Connect a clean hose to an outdoor faucet.

Later in the process you will need to direct this water back into the well. Make sure your hose is positioned properly for this.

 

5. Remove the top off of your well.

If you are unsure how to do this, contact a licensed well contractor.

 

6. Pour all of your Diluted Chlorine into the well.

You will not need to save any of the Chlorine, use all of it in this step.

 

7. Turn on the water and redirect into the well.

Make sure this is the faucet that your hose is connected to. You will need to have this hose redirect into your well. Make sure that it is washing down the sides of the well casing to disinfect it as well.

 

8.  Turn on every tap in your home.

You will need to run every tap in your home to get the Bleach into all of your pipes. Once you smell the Chlorine (The smell of a swimming pool) you will know that it is in your pipes and you can turn off your tap.

 

9. Let the Chlorinated Water Sit.

Now that your tap is turned off, you will want to leave the Chlorinated Water sit in your pipes for 12-24 hours. Meaning no less than 12 hours but no more than 24.

Do not use your water during this time, it will have high levels of Chlorine and shouldn’t be used or consumed. It needs to sit in the pipes to disinfect your system.

 

10. Flush your system.

After waiting 12-24 hours, you will need to flush your system. Run your water from the hose away from the septic system and any landscaping, this chlorinated water can kill grass and flowers.

Then turn on all your other water sources and let them run until the chlorine smell is no longer there.

When flushing your indoor faucets, if you can run them through a hose to go outside that is preferred since Chlorine can be hard on a septic system.

 

After you Shock Chlorination

 

Roughly 2 weeks after you shock chlorinate your well, you will want to test for Total Coliform Bacteria using the Safe Home DIY Bacteria Test Kit. If the Shock Chlorination worked, then this should be negative. If your well test positive for Total Coliform Bacteria, then you will either need a continuous disinfection device or to contact a professional that can try to solve the source of the problem.

 

If you still need help with Shock Chlorination, your local Health Department or a local Water Treatment Professional will be able to help you or give you the resources you need.