Effective infection control is very crucial. The objective of this research is to determine the level of bacterial countin water from dental chair unit output at the Dental Clinic Faculty of Dentistry, UniversitiSains Islam Malaysia. Five dental chair units of treatment rooms were selected. A total of 31 water samples collected from three-way syringe and cup filler water. Positive control was taken from aquarium and distilled water was used as negative control. The nutrient agar was prepared and the samples were cultured immediately in the laboratory. The samples were incubated for 24 hours in 37˚C before observation and the total bacteria counting done. Direct counting method was done in three times by calculating all colonies formed unit in 1 millilitre. The total bacteria count was550 cfu/ml in aquarium, 0 cfu/ml in distilled, (3.40±0.245) cfu/ml in three way syringe and (3.75±0.25) cful/ml in cup filler water. All samples from five dental units showed less than 200 cfu/ml of total bacteria count and meet the American Dental Association recommendation. The Gram staining showed that the colonies of bacteria taken from the samples mostly gram negative bacteria. For conclusion, the filter system and anti-retraction valve used in these five dental units is effective but this system must be timely monitor