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What if my water tests positive for coliform or E. coli bacteria?

The following are some recommended actions to consider if your water test is positive for Coliform bacteria.  Using one or more of these actions will help to ensure safe drinking water for your household.  


  1. Have your water re-tested.  It is possible that the sample became contaminated during the sampling process.  Have a second sample collected by an experienced field technician.   
  2. Have your well shocked:   Shocking your well is NOT as simple as just dumping bleach down your well.  There are considerations and steps that if not followed closely could make you severely ill. Many building inspection companies offer well shocking services, or they can provide an EPA approved do-it-yourself well shocking kit. The Virginia Department of Health also offers instructions via the following weblink on how to shock your well:    
  3. Boil your drinking water or switch to bottled water:  Boiling water at a rolling boil for three minute is the most effective way to remove bacterial organisms from drinking water.     
  4. Add an on-site treatment system:  There are a number of water treatment devices that can be hooked up to your water supply and may prove effective at removing bacteria and other contaminants from your drinking water.  These typically use distillation, chlorination, ozone, ultraviolet light, or some form of filtration.    Note:  Faucet mount or water pitcher filters are typically NOT EPA approved for bacterial removal.  These types of filters are designed to remove mainly chemicals in order to improve taste. 
  5. Look for contamination sources:  Have your well inspected to check your system for damage or incorrect installation.  If your well is located near an agricultural source, or drilled close to your septic system, having a new well sighted and drilled in another location by a certified well installer may be an option.  There is no guarantee however that drilling a new well will solve the problem.
  6. Follow-up Testing:  The Virginia Department of Health recommends that water from private wells should be tested for Coliform bacteria at least once per year.  You should also consider having your water tested after implementing any of the above options to ensure the effectiveness of the chosen treatment(s).