Water Quality

What are Coliform Germs?

In water, Legionella, Coliforms, and other bacteria can multiply rapidly and uncontrollably under ideal conditions, quickly becoming a hazard to consumers. E. coli bacteria, for example, cause nausea, diarrhea, and vomiting. Some bacteria, including Legionella, can even become life-threatening.

Coliform bacteria include a heterogeneous group of anaerobic, rod-shaped bacteria, such as Escherichia, Enterobacter, Klebsiella, and Citrobacter. In particular, the presence of Escherichia coli in drinking water is indicative of fresh fecal contamination. The group of coliform bacteria is therefore considered in the drinking water regulations, as well as in general, as a hygiene indicator in water.

All coliform bacteria can reduce the shelf life of food as putrefactive agents. They are lactose-cleaving and produce acid and gases within 48 hours at 35 degrees Celsius.

These bacteria should not be present in drinking water at all, yet contamination of various causes occurs time and again. These include defective pipes, nearby agricultural facilities, construction work or technical problems in water treatment plants. If the contamination is detected in time, the utility warns citizens and informs them of appropriate protective measures.

In the case of private water treatment plants, the consumer himself is responsible for monitoring. In the case of industrial process water, there is a set of rules to be applied as part of the HACCP concept and other statutory regulations.

Reasons for coliform bacteria in water

The multiplication of bacteria in water occurs mainly in water pipes. Here they find ideal conditions for multiplication. The causes for the occurrence of coliform bacteria can be divided into three areas:

  1. 1. Raw water extraction and waterworks
  2. 2. Distribution network
  3. 3. Drinking water installations in buildings

The reasons for the occurrence of coliform bacteria can be:

  • Inadequate water disinfection or lack of water hygiene.
  • Inadequate water treatment at the waterworks
  • Broken pipes or leaks
  • Bacteria that adhere to sediment can bypass water disinfection
  • Heavily polluted water, for example, by algae (resistance of bacteria increases)
  • Reversal of flow direction and sudden increase in flow velocity
  • Poorly maintained pipe networks
  • Disturbances in the technological flow

Where do Coliform Bacteria Occur?

Coliform bacteria are considered hygiene indicators and their detection are one of the common hygienic test methods for determining water quality. With ever-improving microbiological detection methods, these bacteria can be detected in the water.

Bacteria multiply easily, especially in long pipes and at warm temperatures. Coliform bacteria are considered pathogenic, and potentially disease-causing.

The situation becomes critical whenever microbiological contamination in the form of pathogenic bacteria enters drinking water or occurs in large numbers in raw water, the preliminary stage of drinking water.

Coliform bacteria occur, for example, in drinking water, in the drinking water distribution system, in tap water, bathing water, in well water and wastewater, on foodstuffs, in contaminated elevated tanks, in groundwater and spring water, in drinking water, in swimming and bathing pool water and sewage treatment plants.

For the water supply of private households, public institutions, the industry as well as agriculture, fluctuations in the quality of raw water represent one of the main problems. Therefore, comprehensive water hygiene is important to prevent waterborne diseases.


Nissui Pharmaceutical Co. Ltd. is a Japanese company with nearly 90 years of tradition, mainly engaged in the development and manufacture of clinical and industrial diagnostics and pharmaceuticals. Among the company’s major innovations is the Compact Dry food diagnostic product line.


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