The study was conducted at Wonji town, which is located 110 km south eastern of AddisrnAbaba. The objective of the study was to assess bacteriological and chemical drinking waterrnquality and related impacts on public health. Laboratory analyses of drinking water samples,rnquestionnaires and relevant secondary data were used to generate important informationrnfrom the study. Drinking water samples were collected using standard procedures from pipes,rnriver and house hold water containers and analyzed for coliform bacteria using MPNrntechniques and nitrate, nitrite, ammonia and fluoride using spectrophotometer. The datarnwere analyzed using SPSS software, t-test.rnAverage counts of TC and FC for the water samples from house hold containers ranged fromrn9-126.5 MPN/100 ml and 0-23 MPN/100 ml, respectively. For the water samples from pipesrnand river, the average counts of TC and FC were 1.5-102 MPN/100ml and 0-22.5rnMPN/100ml.The average concentrations of the chemical parameters from analyzed waterrnsamples at the study area were 0.01-0.76 mg/l, 0.0015-0.025mg/l, 1.1-6.15 mg/l and 2.3-rn5.8mg/lfor ammonia-nitrogen, nitrite-nitrogen, nitrate-nitrogen and for fluoride respectively.rnAmong analyzed drinking water samples, 70%, 90% and 100% of the samples were abovernthe WHO recommended guideline limits for TC, FC and fluoride respectively. There fore,rnbased on the results of most water samples, the water is non-potable from bacteriologicalrnand chemical quality points of view.rnThe presence of high counts of total and fecal coliforms in the water samples could indicaternthe fecal contamination and probably the presence of pathogenic organisms in the water thatrncould cause health risks to the community. Out of 128 Wonji high school students selected forrnthe study through questionnaires, 92 (71.88%) of them were affected by dental fluorosis.rnGenerally, the results of the study revealed that drinking water quality was deteriorated andrncaused public health problems. There fore, effective chlorination and defluoridation of waterrnsupplies are very important to improve the drinking water quality and the health of therncommunity at the study area.