AWWA QTC97176

A positive coliform sample collected from a consumer's free flowing faucet can indicate system defects, quality control problems or noise. Noise is generally defined as bacteriological contamination from sources other than the distribution system such as service lines to buildings, corroded building plumbing, faucet fixtures and point of use devices. Although this paper addresses some quality control issues, it focuses on noise and demonstrates how two utilities, the Philadelphia Water Department and the District of Columbia Water and Sewer Authority, implemented measures to reduce noise in bacteriological monitoring.