We assessed the quality of partially treated drinking water in 30 private establishments in Sana'a City, Republic of Yemen. We also compared the assessed water with the quality of 43 private wells and 18 estate wells. Microbiological examinations showed that 83% of the samples were contaminated; 50% with fecal coliforms and 33% with total coliforms. Concentration of mineral exceeded nominal values in 7% of the samples for nitrates, 10% for iron salts and in 20% of the samples for fluorides. In 33% of the samples, fluoride concentrations were lower than normal. Only 16.7% of the samples were found microbiologically and chemically potable.