Well Disinfection 101—DIY Instructions 

Well Water Disinfection

Well disinfection can eliminate or reduce many harmful bacteria and viruses, as well as harmless bacteria that can cause unpleasant water odor and taste.

In this article, we will cover when and how to disinfect your well. 

When Should I Disinfect My Well? 

There are several circumstances that should cause you to consider having your well disinfected. The first, perhaps the most critical instance is if you have had your water tested and the results were unsatisfactory. Bacteria, such as coliform, cryptosporidium, e. coli, and fecal type bacteria can live in your untreated water source and can cause serious health issues. 

Also, you should disinfect your well if you have had major flooding in your area, plumbing repairs or installations, and well or casing repairs. If you begin to notice unusual tastes or smells in your water, it’s probably time for a well disinfection. These are all reactionary measures, but the best policy is prevention. An annual well inspection from C&J offers bacteria sampling and testing, so you can have the best information regarding your water quality. 

Well Water Disinfection

How Can I Disinfect My Own Well? 

Each time you service your well you need to take certain safety precautions. Before you remove your well pump, ensure the power is off to the pump and there are no chaffed wires or missing wire nuts. Instruct the people in your home not to use or drink the water during the disinfection process. Remember to use safety goggles around bleach and other hazardous chemicals. If you have a well pit, don’t enter it without proper respiratory gear, or better yet—contact a licensed well professional. Well water pits can be very dangerous and noxious gases can build up to dangerous levels. 

Step One—Safety Precautions

Once you have taken the necessary precautions, you will want to isolate the critical areas. You need to bypass all softeners, filters, livestock, and bait tanks. This equipment can also be the source of contamination, so refer to the manufacturer or dealer on how to disinfect them. Remember to turn off the power to the well pump and lock out the breaker.

Step Two—Calculate & Mix Chlorine

With the power off, remove the well cap, or seal and set the wires and wire nuts aside. Calculate the amount of bleach to use. Figure 1 gallon of bleach for every 15ft of water in well casing. If the depth of water is unknown, use 3-4 gallons of bleach for the first attempt. Increase the amount of bleach for other purifications. Use the chart below to calculate how much bleach you will need.

Step Three—Add Chlorine to Well

Next, pour the bleach into well and hose it down the sidewalls of the casing. Cap the well and let the bleach solution sit inside the well for about 30 minutes, and then recirculate the chlorinated water.

Step Four—Recirculate Chlorinated Water

To recirculate, turn on the pump power, insert a garden hose into the well, and run the hose until you smell chlorine. While water is circulating, run each inside faucet (including toilets) and outside spigot until you smell bleach, or use chlorine test papers. Open cold water faucets and showerheads. Use cold water only in plumbing. Turn off faucets and showerheads when a strong bleach smell comes through. You may need to remove faucet aerators if the iron from your well is clogging them. Let the chlorinated water sit in the lines for at least 6 hours. 

Step Five—Remove Chlorinated Water

After at least 6 hours, run a garden hose to remove the chlorinated water. This chlorinated water can kill vegetation, so be sure to discharge it in a location where it won’t matter if plants are killed. Do not run this treated water into your septic system, as the amount of water required to flush the system may overload it. Also, running a high concentration of bleach water into your septic system can kill the natural bacteria. This can adversely affect the function of your septic system. Please consult a septic professional with questions. Be sure to rinse all bleach from household plumbing before sampling water.

Step Six—Collect Water Sample

Bleach sample point before sampling. Use calculated laundry bleach in a plastic container and immerse the faucet on the inside and outside. Rinse bleach from the sampling outlet. Run water until freshwater flows from the outlet, at least 5 minutes or more. Finally, collect samples per laboratory instructions. Depending on the result of the sample, you may need to repeat this process. If your sample fails for e.coli, you will also need to chlorinate your water heater and surrounding plumbing.

Unfortunately, disinfecting a well doesn’t cure all water problems.

If this is the case for you, or if you want licensed professionals to disinfect your well, contact C&J today! 



4 INCHES X 0.65 

5 INCHES X 1.00 

6 INCHES X 1.50 

8 INCHES X 2.60 

10 INCHES X 4.10 

12 INCHES X 6.00