How to Safely Chlorinate Your Well: A Step-by-Step Guide

A contaminated well can be a serious health hazard, introducing harmful bacteria, viruses, and other microorganisms into your drinking water. Chlorinating your well is a crucial step in ensuring the water you and your family use is safe. This detailed guide will walk you through the process, providing clear instructions and essential safety information. Whether you’re dealing with a recent contamination or conducting routine maintenance, understanding how to properly chlorinate your well is vital.

Why Chlorinate Your Well?

Well water is susceptible to contamination from various sources, including:

• Surface water runoff: Rain and snowmelt can carry contaminants into the well through cracks in the well casing or surrounding soil.
• Septic systems: Malfunctioning septic systems can leach harmful bacteria and viruses into the groundwater, potentially contaminating nearby wells.
• Animal waste: Runoff from farms and livestock areas can introduce fecal coliform bacteria, which can cause illness.
• Natural groundwater movement: Movement of groundwater can carry contaminants from distant sources to your well.
• Well maintenance and repairs: Any work done on the well can potentially introduce contaminants.

Chlorination is an effective method for disinfecting well water, killing harmful microorganisms. It’s a temporary solution, and regular testing and maintenance are important to maintain water quality. If you have consistent issues, you might want to consider a more permanent solution like an ultraviolet (UV) disinfection system.

When Should You Chlorinate Your Well?

You should consider chlorinating your well under the following circumstances:

• After a new well is drilled: New wells should be disinfected to ensure they are free of contaminants before use.
• After any well maintenance or repairs: Any time you open the well or disturb the system, there’s a risk of introducing contaminants.
• If you experience a positive bacteria test: If a water test reveals the presence of coliform bacteria or other harmful organisms, chlorination is necessary.
• After periods of heavy rainfall or flooding: These events can introduce contaminants into the groundwater and increase the risk of well contamination.
• As a part of regular maintenance: Many homeowners choose to chlorinate their wells annually or every few years as preventative maintenance.
• If your water has an unusual taste or odor: Sometimes, changes in the water’s taste or smell can indicate bacterial growth.

Materials You’ll Need

Before you begin the chlorination process, gather the necessary materials:

• Household bleach (unscented, 5.25% – 8.25% sodium hypochlorite): This is your chlorine source. Avoid using bleaches that contain additives or scents. Be sure to note the concentration, which is usually printed on the label.
• Water: Enough to mix with bleach and flush the system. A garden hose is helpful.
• A measuring container or cup: To accurately measure the bleach.
• A clean bucket or container: For mixing the bleach solution.
• Rubber gloves and safety glasses: To protect yourself from bleach exposure.
• A garden hose: To flush the system and distribute the chlorinated water.
• A timer or clock: To keep track of soaking times.
• Water testing kit: To verify successful disinfection.
• Optional: Activated Carbon Filter: For filtering out the chlorine taste and odor after the chlorination process is complete.

Understanding Bleach Concentration and Dosage

Household bleach typically comes in concentrations ranging from 5.25% to 8.25% sodium hypochlorite. The specific concentration will affect how much bleach you need to use. The goal is to achieve a chlorine concentration of approximately 50-100 parts per million (ppm) in the well water. Here’s a general guideline for calculating the amount of bleach required, based on a standard well casing diameter of 6 inches:

Calculate Well Water Volume:

• Determine the Well Depth: You’ll need to know the depth of your well and the depth of the water level. Use the well log or consult a well professional if you don’t know this. If you only know the total well depth, assume the water depth is around 2/3 of that.
• Standard Well Casing Volume: A 6-inch diameter well casing holds about 1.5 gallons of water per foot.
• Calculate Total Well Volume: Multiply the depth of the water in the well (in feet) by 1.5 gallons/foot.

Calculate Bleach Dosage:

• 5.25% Bleach: Use approximately 3 pints (or 1.5 quarts) of 5.25% bleach for every 100 gallons of water in your well. Or, for smaller volumes, you can use 3/4 of a cup per 25 gallons
• 8.25% Bleach: Use approximately 2 pints (or 1 quart) of 8.25% bleach for every 100 gallons of water in your well. Or, for smaller volumes, you can use 1/2 cup per 25 gallons

Simplified Calculation

For 5.25% bleach: For each 10 feet of water in a 6 inch well casing, add 1 1/2 pints or 3 cups of 5.25% strength bleach. For 8.25% bleach: For each 10 feet of water in a 6 inch well casing, add 1 pint or 2 cups of 8.25% strength bleach. This is a very general guideline; be sure to calculate your specific well’s requirements.

Important Note: These are approximations. It is better to err on the side of a little more bleach than too little.

Example Calculation:

Let’s say you have a well with 50 feet of water in a 6 inch casing. That’s 50 feet X 1.5 gallons/foot = 75 gallons of water. You are using 5.25% bleach, so we multiply 75 gallons by 1.5 pints/100 gallons. 75 X 1.5/100 = 1.125 pints of bleach. 1 pint is equal to 2 cups so we’re dealing with roughly 2.25 cups. In this scenario, it would be fine to round up to 2.5 cups. Remember, it is better to add a little more than too little.

Step-by-Step Chlorination Process

Follow these steps carefully to ensure proper chlorination and safety:

Step 1: Prepare the Well

1. Turn off the well pump power: Locate the circuit breaker for your well pump and switch it off. This prevents the pump from running during the initial chlorination process.
2. Remove any filters or treatment systems: Bypass or remove any water treatment systems, such as water softeners, sediment filters, or carbon filters, before chlorination. Chlorine can damage these systems.
3. Clean around the well casing: Remove any debris, leaves, or other materials from around the well casing and well head.
4. Ensure the well cap is secure: Check to make sure that the well cap is securely attached and there are no gaps or cracks where contaminants can enter the well.

Step 2: Mix the Bleach Solution

1. Put on safety gear: Wear rubber gloves and safety glasses to protect your skin and eyes from bleach exposure.
2. Prepare a clean bucket: Use a clean bucket or container for mixing the bleach solution.
3. Measure the correct amount of bleach: Carefully measure the amount of household bleach based on your well’s calculated volume and concentration, using a clean measuring cup or container. Double check to ensure the concentration on the container is what you expect.
4. Add the bleach to the bucket: Pour the measured bleach into the bucket.
5. Add water to the bucket : Add about a gallon of water to the bucket. This helps dilute the bleach making it easier to pour into the well.
6. Stir the mixture: Stir the bleach solution gently with a clean stick or plastic utensil. Do not use your hands or any metal materials.

Step 3: Introduce the Bleach Solution to the Well

1. Remove the well cap: Carefully remove the well cap, being mindful of any contaminants that might be on the cap.
2. Pour the bleach solution into the well: Carefully pour the mixed bleach solution into the well casing, avoiding any splashing or spilling.
3. Rinse the bucket: Rinse the bleach bucket several times with clean water and pour the rinse water into the well.

Step 4: Circulate the Chlorinated Water

1. Turn the well pump power back on: Restore power to the well pump by flipping the circuit breaker back to the on position.
2. Run water in the house: Turn on all cold water faucets in your house, including outdoor spigots. Let the water run until you smell the chlorine.
3. Circulate the chlorinated water: Run each tap in the house until you smell chlorine, ensuring the chlorinated water is circulating throughout your plumbing system.
4. Turn faucets off: Once each tap has a chlorine smell, turn off all the water faucets.

Step 5: Soak the Well and Plumbing System

1. Allow the chlorinated water to sit: Let the chlorinated water sit in the well and plumbing system for a minimum of 12 hours, and ideally 24 hours. This allows the chlorine to effectively kill any bacteria or other contaminants.
2. Do not use the water: During the soak period, do not use any water from the well for drinking, bathing, or any other purpose.

Step 6: Flush the System

1. Connect a garden hose: Connect a garden hose to an outside faucet.
2. Run the water outside: Turn on the faucet and run the water through the garden hose, directing it to an area where the chlorinated water will not cause harm, such as a grassy area away from your yard or a ditch. It is also a good idea to avoid flushing the chlorinated water into a septic system.
3. Flush the system thoroughly: Continue to flush the system until there is no longer a chlorine odor. This can take a significant amount of time and water, depending on your well and plumbing system’s complexity.
4. Run indoor taps: Run all indoor taps, one by one, until there is no chlorine smell.

Step 7: Retest Your Water

1. Wait at least 24 hours: After flushing your well, wait for at least 24 hours before taking a water sample for testing.
2. Collect a water sample: Collect a water sample from a faucet you frequently use. Make sure to use a sterile container.
3. Test the sample: Have your water sample tested by a certified laboratory to ensure that the bacteria are completely eliminated.
4. Retreat if needed: If the test results still indicate the presence of bacteria, repeat the chlorination process or contact a well professional for further assistance.

Optional Step 8: Use Activated Carbon Filter

1. Install activated carbon filter: If your household filter system has an activated carbon filter, install it in order to remove chlorine taste and odor from the water supply.
2. Flush system again: Flush your indoor taps for a few minutes to make sure any remaining chlorine is removed.

Safety Precautions

• Always wear protective gear: Protect your eyes and skin from bleach exposure.
• Avoid inhaling chlorine fumes: Work in a well-ventilated area, especially when handling bleach.
• Do not mix bleach with other chemicals: Mixing bleach with other cleaning products can produce toxic fumes.
• Keep children and pets away: Ensure that children and pets are kept away from the well and any bleach solutions during the process.
• Do not drink or use the water during the soak period: During the soak period, do not use water from the well for consumption or any other purposes.
• Properly dispose of containers: Dispose of the bleach containers responsibly after use.

When to Call a Professional

While chlorinating your well is a manageable task for many homeowners, some situations require the expertise of a professional:

• If you’re uncomfortable with the process: If you feel unsure or hesitant about any part of the chlorination process, it’s best to call a well drilling or water treatment professional.
• If problems persist: If repeated chlorination does not resolve the contamination issues, there may be a more serious underlying problem that requires a professional assessment.
• If you’re unsure about your well’s construction: If you are uncertain about your well’s depth or casing material, a professional can accurately assess the situation.
• If you have a complicated system: If you have a complex water system with multiple tanks, filters, or treatment equipment, professional guidance may be necessary.

Additional Tips

• Keep detailed records: Document each time you chlorinate your well, including the date, time, amount of bleach used, and any test results.
• Regularly test your water: Have your well water tested annually, or more frequently if you suspect contamination.
• Maintain your well and system: Take good care of your well cap, casing, and other components to help prevent contamination. Regularly inspect the well for cracks or damage.
• Address sources of contamination: If you have an idea where the contamination is coming from (such as a leaking septic system), address that problem to prevent future contamination.
• Consider an alternative treatment system: If you have repeated contamination issues, consider installing a more permanent treatment system, such as an ultraviolet (UV) disinfection system, or a chlorination system.

Conclusion

Chlorinating your well is a crucial step in ensuring the safety of your drinking water. By following these detailed steps and taking necessary precautions, you can effectively disinfect your well and protect your family from harmful contaminants. Remember that regular maintenance and testing are key to maintaining a safe and reliable water supply. If you have any doubts or concerns, don’t hesitate to consult a qualified well professional.