Can bacteria in water make me sick?

The transmission of disease through drinking water is one of the primary concerns for a safe water supply. Human illnesses such as typhoid, dysentery, chlorea, hepatitis, and giardiasis have been linked to drinking water contaminated by human waste.

Can bacteria in water affect livestock?

Bacteria levels for livestock vary with intended water use (Table 1). Adult animals are more tolerant of bacteria than young animals. Water for cleaning and sanitizing must be of very high quality to prevent infections and contamination of food products.

How to tell if water is contaminated with bacteria.

Testing a water supply for a specific diseasecausing organisms is expensive. Handling and culturing disease organisms requires special training and equipment. Also, if the water supply is being contaminated by human wastes, but the disease organism is not present the day a sample is taken, the risk of future exposure to the illness is still present.

Instead, water supplies are tested for an indicator of human or animal waste-coliform bacteria. Coliforms do not cause disease. They are, however, always present in the digestive systems of humans and animals and can be found in their wastes. Coliforms are also present in the soil and plant material.

If a water supply is found to contain coliform bacteria it may be contaminated by sewage or manure, and there is a risk of exposure to water-borne disease. The test for coliform bacteria is relatively inexpensive (usually $6 to $15 per sample) and easy to perform.

To determine whether the bacteria present is from human or animal waste, additional tests must be performed. Coliform bacteria also could come from natural sources such as soil or decaying vegetation. Some coliform bacteria are only present in fecal material; these are called fecal coliforms. These bacteria indicate the presence of human or animal waste.

A test for a third bacteria, fecal streptococci, must be performed to determine if it is of human or animal origin. The ratio of fecal coliforms to fecal streptococci vary for different animals (Table 2). If the ratio is near four, the waste is from humans. The ratio is less than one for animal wastes.

Another type of bacteria, referred to as iron bacteria, is a major nuisance in many well water supplies. (Iron bacteria should not to be confused with iron dissolved in water that causes red water and stains on clothing and plumbing fixtures.) This naturallyoccurring bacteria does not cause disease, but does form a reddishbrown slime that coats the inside of pipes, fouls pumps and clogs waterers.