The aim of this study was to evaluate the role of decentralized municipal desalination plants in removal of physical, chemical and microbial parameters from drinking water in Bushehr, Iran and compare the quality of outlet water with guidelines for drinking water. Fifty samples were taken from 10 decentralized municipal desalination plants (five times from every station). The mean values of physical, chemical and microbial parameters in outlet water were electrical conductivity (322.08 μS/cm), turbidity (0.0 NTU), pH (6.84), alkalinity (61.2 mg/L), carbonate (0 mg/L), bicarbonate (61.2 mg/L), total hardness (82.96 mg/L), calcium hardness (73.8 mg/L), magnesium hardness (18.96 mg/L) as CaCO3, calcium (29.52 mg/L), magnesium (4.72 mg/L), residual chlorine (0.37 mg/L), chloride (25.61 mg/L), TDS (161.04 mg/L), iron (0.045), fluoride (0.167 mg/L), nitrate (1.71 mg/L), nitrite (0.0026 mg/L), sulphate (107.17 mg/L), total coliform (0), fecal coliform (0) (MPN/100 mL) and HPC (322.9 CFU/mL). Our results showed that 10% of HPC outlet samples did not comply with the Iranian National Regulation (INR), Environmental Protection Agency (EPA), and World Health Organization (WHO) guidelines. The mean levels of examined parameters in desalination plants' outlets generally complied with the INR, EPA and WHO guidelines. Decentralized municipal desalination plants efficiency in removal of measured parameters were in the range of 18.52 (in the case of nitrite) to 100% (in the case of turbidity).