Home Building Articles

Disinfecting your Well in 5 Easy Steps

Follow these directions for disinfecting your well if your water has coliform bacteria in it. This disinfection process treats only biological contaminants, not chemical or mineral contaminants.

  1. Flush the System
    • If your water is cloudy, let the water run for 10-15 minutes before disinfecting.
  2. Chlorinate the Well
    • Use household bleach which typically has a chlorine concentration of 6%. Do not use "ultra" concentrated bleach or bleach products with additives or perfumes. The amount of bleach to use is according to the chart below.
    • Mix bleach in a bucket of water.Remove well cap, plug, or vent (see diagram); using a funnel, pour the bleach into your well.
  3. Mix the Bleach with the Well Water
    • Attach a hose to the nearest outside faucet and allow the water to run onto the ground for 1-2 minutes until you smell chlorine. Then place the hose in the hole where you poured to bleach, allow the water to turn back into the well for 15-20 minutes.
    • Remove the hose and replace the well cap, plug, or vent.
  4. Chlorinate the Lines
    • Turn on each tap attached to well (kitchen, bathroom, outdoor spigot, etc.), starting with the nearest tap to the well, and let the water run until you smell blach, trun off and then go to the next tap.
    • Turn off electricity to the pump and let sit (12 hours or overnight).
  5. Flush the Chlorinated Water Out of the System
    • Choose any outdoor spigot and let the water run onto the ground, away from your septic system (also keep water flow from going into creeks, streams, or where fish or vegetation can be harmed), until you no longer smell bleach. This empties the bleach from the well.
    • Turn on each faucet inside the house until you no longer smell bleach.
    • Once the system has been flushed of all bleach, the water can be used for laundry and bathing but you should not yet use it for drinking, brushing teeth, making ice or preparing food.
    • Wait 3-4 days after flushing the bleach out to collect coliform bacteria samples. You may need to repeat this process several times before coliform test results are "satisfactory". Also, be aware that the bleach may disturb built-up minerals in your pipes and temporarily discolor your water. This discoloration should disappear once the bleach is flushed out of your system.

*1 gallon bleach for 300 – 400 ft. well

Additional Steps:

  • Run dishwasher & change filter in refrigerator
  • Flush toilets 2 times
Well Chlorine Dosage