The safety of any municipal water supply is determined by biological and chemical factors.Safety means that biological risk factors which could cause water-borne illness from virus, bacteria, and parasites, are eliminated by treating the water with disinfectants like chlorine or chloramines. In terms of chemical safety, Edmonton monitors both naturally occurring chemicals and chemicals that leach into our water supply like road salt. In older Edmonton neighborhoods with lead supply lines, the city also helps people manage that risk by alerting residents. Managing these safety standards means that we must accept the risks associated with the chemical disinfectants cities must use.