I really like the Vermont Department of Health Coliform in Water Webpage. It takes this topic and give you straight-forward water.
(Any levels of coliform in water are cause for concern and action should be taken) – This is really what you need to know when it comes to determining if your water is safe to drink or not.
What type of action should a person take in trying to eliminate coliform in water?
If coliform bacteria is detected in your drinking water supply, visually inspect your system. Look for leaks, unmortered joints, loose caps, ripped vents screens, etc. Attempt to identify any known sources of bacterial contamination in the area surrounding the well. Repair any deficiencies noted.
Once repairs have been made, shock chlorinate your well in order to sanitize the system. (Refer to the handout, “Disinfection” for instructions.) Once the cholorine odor is gone, retest your water. If the bacterial problem continues, even after shock chlorinating several times, consider permanent treatment for your water supply. Treatment options include installing a chlorinator that injects precise amounts of chlorine into your home’s plumbing system when the water is being pumped to the home taps, or ultraviolet light treatment preceded by a filter when appropriate. Water treatment professionals who specialize in these treatment devices can be found in the yellow pages.
Source: Vermont Department of Health
If you have questions regarding your water, have it tested and determine if your water is first, safe to drink and secondly, potential issues which should be monitored or addressed.
For more information on water testing, check out the water analysis packages available at Midwest Laboratories.