What does it mean if I have Coliform bacteria present in my well?

Coliform bacteria live on the surface of the earth. Coliform bacteria should not be in a properly sealed cased well.

Coliform bacteria in a well means:

1) the water system has been worked on (a broken line repaired or a pump or tank replaced) but the system was not adequately disinfected afterward – remember materials used in water systems have often been on ships, shipyards, stored outside or laid on the ground – these are not clean items.

2) there is a path from the ground surface to the well aquifer. This is often not visible and can happen even under a cement pad.

3) the well construction is no longer holding out the surface water. Perhaps the top of the well does not extend 12-18 inches above ground or the seal needs replacement. It is critical that the problem be located. Basically, the well is allowing the aquifer to be contaminated. It is illegal to contaminate a confined aquifer in Oregon. Remember: Placing treatment on the well does not stop the contamination of the aquifer.