The Wastewater Utility includes wastewater collection and maintenance, industrial pretreatment, and wastewater treatment and monitoring before water is discharged to Boulder Creek. The city's wastewater treatment plant is located seven miles east of Boulder and is the collection point for sewers throughout the City. Approximately 16 million gallons of wastewater are collected each day from homes, businesses, schools, and anywhere a water tap exists. Industrial businesses are required to meet City discharge limits and may need to pre-treat their wastes prior to discharge into the City's sewer system. Chemicals used in the home can also affect water quality and should not be disposed through the sewer system but through a hazardous waste collection program.
Boulder County operates a household hazardous waste facility on an appointment-only basis.
Solids are removed, and the liquid waste stream passes through a series of biological treatment systems, clarification, disinfection, and monitoring before discharge to Boulder Creek. Wastewater solids are biologically broken down and stabilized to yield a humus with excellent soil amending properties and fertilizer value. The product is used as an additive to the region's sand and clay soil and has been shown to increase productivity on both open space and private farming land. The methane gas which is formed during the solids stabilization process powers a generator system which produces electricity for operation of the treatment plant or for resale to Public Service Company.