Tuesday, July 9, 2013

Question Regarding Chlorine Disinfection of Well

Our well water tested positive for coliform but I can't get information about the depth of the well. The cap measures 6" diameter (with the wiring to the submersible pump visible). The house has 3 full and two half bathrooms.

Can you make a rough estimate on the depth of this well so I can figure the amount of bleach to add?

Also, do you think the treated water's chlorine level might be safe enough to discharge from our sprinkler system?

I've heard that the aeration significantly reduces the chlorine concentration and might be safe. Many thanks.



Phil –

well head seal
You could first just estimate that it is about 100 feet deep, and use 1 to 2 quarts of household bleach to start with. Mix in with 5 to 10 gallons of water and pour that down the well, and then recirculate the water by using a garden hose and allowing the water to run back down into the well, washing down the casing.

Regarding chlorine hurting the landscaping, it is hard to say for sure, but its not likely to cause problems.  We have many customers who are nurseries and growers who chlorinate their water, and they reported that plants can generally take up to about 10 ppm of chlorine.

well system
When you shock-chlorinate the well water, the water can sometimes be as high as 50 to 200 ppm , so you might be able to use it on trees or grass. I would guess it would not hurt a lawn or trees, but you would not know unless you tested the water first for chlorine residuals.

I would recommend you use a high range chlorine test kit when sanitizing your water well.

well diagram house