What you need to know about bacteria in water

Private water well owners are in a unique position—they control their own water supply. With this benefit comes some responsibilities. Private well owners are responsible for protecting their ground water resource as well as their family’s health. Occasionally, based on a news report or the color or smell of the water, well owners may wonder about the safety of their water supply. What can they do? Testing water for the most common well contaminants is the best course of action. The following information from the National Ground Water Association (NGWA) also may answer some of your questions:

How common are water problems?

“Pure” water does not exist—all natural water contains some gases and minerals, and is likely to contain some microbial organisms. Most water bacteria are harmless and many are actually beneficial. Coliform bacteria is one form of bacteria. Coliform bacteria originate as organisms in soil or vegetation and in the intestinal tract of warmblooded animals (fecal coli). The many sources of bacterial pollution include runoff from woodlands, pastures and feedlots; septic tanks and sewage plants; and animals (wild or domestic).

Will coliform bacteria make us sick?

Maybe, maybe not. Most coliforms are harmless residents of soil and will not make people sick. Some strains of E. coli, the most common fecal coliform bacterium, may be pathogens. Some found in food have been lethal. Their presence should be taken very seriously. One might ask, “If my water is clear and smells OK, is it safe?” You cannot directly smell unsafe bacteria or protozoa. They can only be detected using tests designed for that purpose. Therefore, water quality should be checked regularly. NGWA recommends an annual check of water quality and well maintenance, unless changes in water quality suggest the need to test the water at a lesser interval. For instance, some sources of odors are bacteria or septic, or the presence of chemicals. It is a good idea to take your nose seriously. Have the water tested.

What is the “iron bacteria” problem?

Better described as iron biofouling, it consists of biofilms, which include living and dead bacteria, their sheaths, stalks, secretions and other leavings, and embedded metal hydroxide particles. “Iron bacteria” is one type of biofouling among several, including the white sulfur slime of sulfur springs. Manganese and even aluminum biofouling also are found in ground water systems. These biofilms are natural and usually harmless. Natural iron biofouling often acts as a preliminary iron filter in wells and, therefore, can serve a positive function as well. Biofouling can be a nuisance, however. Generally, iron biofouling is the cause of iron buildup in wells and pipes.

If I have bacteria in my well, where do they come from?

Many types of bacteria are native or adapted to saturated sediments and rock, and are present in significant numbers in most water supply aquifers, even deep formations. Given time and a route (soil and rock provide plenty of both), bacteria will migrate into and take up housekeeping in an aquifer. “Non-native” coliform bacterial or “protozoa” of potential health concerns, such as Giardia and Cryptosporidium, are most likely introduced from the surface.

What do we do about this problem?

If possible, do whatever it takes to correct the problem in your existing system. Sometimes this may even involve a new well and water inlet system away from the source of contamination.

What’s the best way to maintain my good water supply?

You should have your water tested annually for radon, bacteria and anything else of concern to you, even if you do not perceive a change in your water. Have your water tested by a qualified laboratory. They are listed in your phone book under “Water Testing” or “Laboratories.” The question of whether to have water tested is a serious one that concerns the health of the families who use it. Those who obtain drinking water from privately owned wells are responsible for assuring that it is safe.

Where can I get more information?

For more information, contact a local ground water contractor or the U.S. EPA’s Safe Drinking Water Hotline at 800-426-4791. You can find an NGWA member contractor near you by going to www.wellowner.org and clicking on “Contractor Lookup” at the top of the page.

From the May 18-24, 2005, issue

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