Water quality modeling in distribution systems

The Safe Drinking Water Act and its amendments have been interpreted as requiring that maximum contaminant levels established under the Act, be met at the consumer's tap. This interpretation has increased interest on the part of the U.S. Environmental Protection Agency (EPA), state regulatory agencies, and drinking water utilities in the factors that result in water quality deterioration between the treatment plant and the consumer's tap. The hydraulics of mixing, cross connections, loss of system integrity, and the growth and decay of chemical and microbiological contaminants can play a major role in lowering water quality in distribution systems. Models that provide insight into the factors that result in water quality deterioration are described and discussed in this paper.