It is not unusual to have an occasional well water test indicate the presence of bacteria, especially if you own an older home where the well is buried under ground. However, the water should be considered at risk until you find out where the problem originates. Do not consume the water unless it is first boiled for at least 15 minutes. Consider using bottled water for drinking and cooking.
If bacterial contamination recurs, then it is recommended that you have the well inspected by a reputable well water contractor for defects or code deficiencies and to upgrade your well water supply accordingly. If there is public water available we recommend that you connect to it.

If the well has evidence of problems that cannot be resolved, a new well may be needed.

"Evaluating Private Well Chemical Sampling Results"

www.dph.state.ct.us/Publications.BCH/EEOH/sampling2.pdf

National Ground Water Association (www.ngwa.org)

Other tips for well owners

• If you are concerned about your well or water testing, check ESDHD for well completion report (depth, yield, and location)
• Be aware that some of these test indicate that your well is not water tight and may be susceptible to surface water contamination
• Shallow wells are difficult to treat; They allow the entrance of vermin/ insects
• Shallow and dug wells can go dry or have quantity issues
• Most new drilled wells have a yield of ~1-8 gpm, avg. depth 100-200'
• Do I have enough water (1 gpm= 1440 gpd; national average ~50 gpd/ person
• A 6" well will hold one gallon of water per foot of well
• Wells with low yield may need additional storage tanks
• If you own a pool and a well, consider using a water tanker to fill pool