How to Chlorinate a Private Well – 10 easy steps!

If you are chlorinating your well, chances are you have tested positive for bacteria. The well chlorination process is simple, but time consuming. Tests fail because:  #1 – people don’t add enough chlorine and #2- don’t give enough contact time. So be patient! This takes at least TWO DAYS!

STEP ONE: Get your supplies together…Bleach and a garden hoseHose for Well ChlorinationBleach for Well Chlorination

1.    Determine the depth of your well.
a.    Town hall may have that information
b.    Your pump installer may have that information
c.    You may have to guess
2.    Determine how much bleach you need.
a.    Use 1 quart of bleach for every 100 feet of water in your well (with a 6” casing).
b.    If you don’t know the depth, you will have to guess
3.    Buy unscented household bleach – 5.25% sodium hypochlorite. Buy 3 gallons if you don’t know the depth.
4.    Get a hose/s long enough to go from your pressure tank or outside faucet to your well.

STEP TWO: Get Ready

1.    Consider filling you’re your bathtub with water just to have.
2.    Do any last minute laundry
3.    Put any water treatment equipment in bypass and take out the sediment filter
4.    Tell everyone in your home they cannot use any water for 8-12 hours.
5.    Turn the water off to the house (in case someone uses it by accident)
6.    Run your garden hose from your storage tank or outside faucet to your well
7.    Remove the well cap. PLEASE INSPECT THE WELL WIRES CAREFULLY. MAKE SURE THERE ARE NO BARE SPOTS THAT YOU ACCIDENTALLY TOUCH.  You can either leave the pump wires where they are, or move them out of the way.
8.    If you do NOT have a well cap, you probably have a well seal that has a ½” vent pipe. You will introduce the chlorine there.

STEP THREE: Chlorinate the Well

1.    Pour the bleach into your well or through the ½” vent pipe. (Remember, 1 quart per 100 feet, or start with one quart if you don’t know the depth)
2.    Put the end of your hose into the well and turn the water on
3.    Run the water (which is circulating water/bleach from the well to your pressure tank and back to your well through the hose)
4.    Every few minutes, smell the water until you smell chlorine. If you do not smell any chlorine after 10 minutes, add another quart of bleach and continue to circulate the water back into the well. Repeat until you smell chlorine.
5.    Once you smell chlorine, wash the inside of the well casing with the bleach scented water.
6.    Put the well cap back on but don’t put the bolts on. You will need access again.

STEP FOUR: Chlorinate the house

1.    Shut the water off to the well.
2.    Turn the water back on to the house
3.    Run the hot and cold water into your washing machine until you smell the bleach.
4.    Run the dishwasher water until you smell bleach.
5.    Run the cold water at one faucet until you smell bleach- then shut the water off.
6.    Run the hot water at one faucet until you smell bleach- then shut the water off.
7.    Repeat those two steps for EVERY faucet, including the tub, shower, toilets (yes you have to smell the toilet water!), and outside faucets.
8.    Do NOT run water for longer than needed. This will put chlorine into your septic tank which you should try to avoid as much as possible.


1.    Now that your well and plumbing have chlorine, leave it alone for at least 8 hours.
2.    It is OK if you flush the toilet 1-2 times.

STEP SIX: Purge the chlorine from your WELL

1.    Use that same garden hose and find a place where you can SAFELY run water. Remember, it will have chlorine and lots of iron (if you have iron).
2.    Do NOT put that water into a stream or back into your well. Do not water your garden or fill your pool, or get even with your neighbor. It may also kill your grass, so pick your spot carefully.
3.    Turn your water off to your home as a precaution.
4.    Run your water from the hose for 20 minutes. If you know the limitations of your well, you can run the water for more or less time. If you notice a pressure drop, then stop running water and let the well recover for an hour.
5.    After running your water 20 minutes, shut the water off and wait 20 minutes.
6.    Repeat this step until the chlorine odor is gone. This could take one hour or three days. It all depends on your well.
7.    Go back to your well with the hose and wash down the inside casing.
8.    Put the cover back on with the bolts.

STEP SEVEN: Purge the chlorine from your HOUSE

1.    Once the chlorine odor is gone from your well, turn the water back on to your house.
2.    Run hot water from you bathtub until the chlorine odor is gone. This could take a while depending on how much storage capacity your hot water tank holds.
3.    Now run hot and cold water from all your faucets.
4.    This should only take a few minutes since you are only purging chlorine that is left in your household plumbing.

STEP EIGHT: Put your water treatment back on line

1.    Put your water treatment back on line and in service position. Make sure the time of day is correct since you are there anyway.
2.    Wipe the inside of your sediment filter with a bleach solution before putting in a new filter. You should be doing this every time you normally change the filter.
3.    As an extra precaution, you could add 1 ounce of chlorine to your salt tank and put your softener through a regeneration. Remember not to use any water during the two hour cycle.
4.    Other water treatment equipment requires professional disinfecting service. Most times, even when you “ignore” the other equipment, the bacteria free water seems to flush it out.

STEP NINE: Retest for bacteria

1.    Bring a new water sample to your lab. Make SURE it does not have any chlorine left since this will void the test. You might have someone else smell the water since your nose may have gotten use to the chlorine smell.

STEP TEN: Celebrate. You’re done and hopefully have bacteria free water!

•    Chlorine loves to party with iron so if you have iron in your water, your water could run very orange or red after the chlorine is introduced.
•    To reduce the amount of iron into your home, remember to STOP running water as soon as you smell chlorine from your hose when you are outside at the well.
•     Also, STOP running water at each faucet as soon as you smell the chlorine.
•    Despite what others may tell you, your water treatment equipment DOES NOT LIKE that dirty, smelly water from a well chlorination.
•    And if you run that YUCKY water through the water treatment equipment, you may RUIN the media and then have to pay for COSTLY repairs.
•    Your faucets and washing machine usually have screens that may get clogged. Be sure to clean them if you notice pressure drops.
•    Hard to avoid but if you have a jet pump, it is possible the foot valve screen or parts inside the jet pump could get clogged. No way to avoid that. Be prepared if it does.

One thought on “How to Chlorinate a Private Well – 10 easy steps!

Comments are closed.