Well Chlorination

Typically, once a year water sources undergo a coliform bacteria test, which analyzes for a bacterial species that can cause changes your water’s taste, smell, or appearance. Most of the bacteria species identified are not harmful, but there are a few that are. Presence of certain types indicate that surface contamination has found its way into the well and that disease organisms may also be present.  Among  the species that present serious health risks are E. coli and fecal coliform. If either of these is present the water should not be used for drinking, cooking, making ice, brushing teeth, dishwashing or human contact.
Contaminated water may contain harmful bacteria, viruses, or other microorganisms that can make you sick. Disinfection is one process of killing or inactivating microorganisms to make water safe for drinking. Disinfection can also eliminate nuisance bacteria that can cause unpleasant tastes and odors. Well chlorination is the method used to disinfect wells.

Well chlorination will help clean the water after you receive word that your water testing result is positive. (Positive means that there is bacteria in your water. Negative means that your water does not contain bacteria.) It can  also help if you have stinky, sulfur-smelling water, although this is not a long term fix. Usually this only eliminates the smell for 2 weeks to 6 months.

Well chlorination should be performed:

  • When water testing indicates the presence of coliform bacteria.
  • When the well has been near flood waters.
  • After installation or repair of plumbing pipes and fixtures, e.g., softeners, faucets, and filters.
  • After well or pump repairs.
  • When iron or sulfur bacteria reduce the water supply capacity of the well or cause taste and odor problems.
  • During startup of seasonal wells where plumbing, wells, or pumps have been disconnected, or the water system has otherwise been drained or opened.

If your well has failed a water test, Fideldy Bros Well Drilling will come to your property with a granular chlorine solution, and with the electrical power turned off to the well system, insert a pipe past the ground connection of your well, pouring 200 gallons of the granular chlorine solution into the well system as quickly as possible, causing the bacteria to be attacked by the chlorine. The water must not be used for 12-24 hours after the chlorine solution is introduced to the well. At the end of that time the water will need to be pumped out of the well with a hose to the outside of any structures as a lot of bacteria, iron, rust, and other contaminants will have been knocked loose by the chlorine.


Well chlorination will not solve the following problems:

  • When contamination is originating from a continuous source such as a septic system or an animal feedlot.
  • When a well or plumbing system is improperly constructed, located, or damaged and in need of repair (disinfection should follow repair work).
  • If the contaminant is nitrate, arsenic, fuel, pesticides, or other chemicals.