Hi everyone,

I'm having problems with my well and would appreciate any help you can offer. Here's the short version of the story.

A year and half ago we found out the well had coliform bacteria (no fecal coliform). It was shock treated and tested OK. Last month it tested positive again. I shock treated it twice, but it still tests positive. From the smell and visual inspection, we also have a problem with iron and/or sulphur bacteria.

There are three septic tanks on the property. The inspections said they were sited far enough from the well.

My questions:

- Where is the coliform coming from? Why is it returning?

- Could a septic be the cause? Some people have said that since there is no fecal coliform, the problem is not coming from a septic. One person said this might not be true.

- Why did the shock treatment not work?

- Do we need a new well?

- Would the new well become contaminated?

- Is the iron/sulphur bacteria interfering with the shock treatment?

- Given the problems we've had, does it make more sense to just treat the water after it comes out of the well?

- Are there other options than a new well or water treatment? Did I do the shock treatment wrong?

Below are more details for those with the patience. Sorry for the length, but I want to give enough info to people who might be able to help.



The details:

The well is 150 feet deep, 4 inch casing. The well feeds three houses on the property. I don't know the age, but the well company says it will probably need to be replaced soon. Even though it's old, getting several more years of life out of it would help, given our current financial situation.

We bought the property a year and a half ago. During the sale, the well was tested and came back positive for coliform. I assume that the previous owners did not know of the contamination, or else they would have treated it before they put it on the market. Why risk undermining a sale, when they knew they would have to treat it anyway. So, I'm assuming the contamination has been there for some time. They owned the house for the previous 15 years.

The well company treated the well. I didn't pay too close attention, but I believe they used some kind of dry, granular chlorine, not pellets. I ran the water through all the fixtures, as directed by the well company. I had a hard time telling by smell whether enough chlorine was coming out, especially after doing three houses. But after finishing, the water tested fine.

Last month, we did a follow-up test. It tested positive for total coliform. I did the shock treatment myself, using several quarts of 6% household bleach, in a single application. This was calculated to give a concentration of about 50 ppm. I flushed the water down the casing, ran it through the fixtures, and let it sit. Again I had difficulty knowing there was enough chlorine. The water still tested positive for coliform.

I repeated the shock treatment. This time I used high range chlorine test strips. I added chlorine then cycled it through the system using a hose for about 20 minutes. The strips showed 300+ ppm. I ran it through the fixtures, checking the chlorine level each time. When the level dropped below 300 ppm, I added more chlorine and cycled. When I finished, I added more and cycled it, so that there was a high level left in the well. It sat for about 15 hours. All told, I used about 2 gallons of 6% bleach in four applications.

After all this, it still tests positive.