Daily Laboratories is one of the few laboratories that perform the microbial water suitability test on a weekly basis for municipal water supplies. This test is listed on the EPA laboratory evaluation form as laboratory pure water bacteriological quality or ratio of growth rate. This test is required at least annually by the EPA and state health departments for water laboratories as part of the intralaboratory quality control practices. The test is complex, requires skill and experience, and is not easily done on an infrequent basis. It requires work over 4 days, an independent ultrapure water, high purity reagents, and aseptic technique. The test is very sensitive to toxic agents or growth-promoting substances.