The increasing demand for potable water in Southeast Asia warrants the need for a simple, rapid, and economical water quality test that can be used by unskilled personnel to monitor potential fecal contamination of drinking water supplies. The coliphage test is expected to fulfill this need since many advantages can be attributed to this test.

In order to evaluate the use of the coliphage test, an intensive study to correlate the results of the coliphage test with three other water quality tests—viz., conventional five-tube most probable number (MPN) fermentation test, the A1 broth five-tube MPN test, and the membrane filtration test—was carried out. At least 1000 water samples were examined over a 20-month period. Results of the tests showed that there is a consistent relationship between coliphages and fecal coliforms in river water, pond water, well water and rainwater, in that coliphages are frequently found when fecal coliforms are detected. On the other hand, correlation analyses have also showed that in water sources that are shallow and turbid due to residual sediments, correlation between coliphages and fecal coliforms was less significant. Further analyses have also indicated that the factors that most affected the coliphage tests were turbidity, pH, and dissolved oxygen. In the process of evaluating the coliphage procedure, it was found that the test can be performed at ambient temperatures and results can be obtained after 6–8 h of incubation.