Bacteria Testing

Bacteria Testing

How often should I test my well water for bacteria?

You should test your well every year for bacteria. In addition, test for bacteria if:
  • You notice a sudden change in your water's taste, appearance, or odor.
  • The water turns cloudy after rainfall or the top of the well was flooded.
  • You suspect a contamination source (sewage system, barnyard, etc.) is within 50 feet of your well.
  • Family members are experiencing unexplained flu-like symptoms.
  • Your water supply system has been serviced or you have made changes to the system. 


How do I test my well water for bacteria?

  • Obtain sample bottles from a Certified Drinking Water Laboratory.
  • When you are ready to sample, remove the aerator from the faucet, if possible. (If the aerator is difficult to remove, just leave it on). Dip the tip of the faucet into a small container of bleach for 30 seconds. Leave the bleach on the faucet for 5 minutes to kill any bacteria present.
  • After disinfection, turn on the cold water full stream and let it run for 15-20 minutes. While the water is running, remove the lid from the sample bottle. DO NOT touch the interior of the bottle or lid. Also, leave any pill or powder in the bottle! Turn the faucet down to a small stream and collect the sample. Fill the bottle up to the neck of the bottle (but don't overflow!) and replace the lid.
  • Put the aerator back on the faucet.
  • Return the sample to Certified Drinking Water Laboratory.  It is best to collect the sample just before delivery to the lab. Samples should be refrigerated or chilled while stored or transported.
  • If you receive a notice that your sample is positive for bacteria, you may want to disinfect your well.


For more information, please contact:

  • Area Sanitarian (based on your Township)
  • Livingston County Environmental Health Division - (517) 546-9858
  • Bacteria Brochure from Michigan Department of Environmental Quality