The City of Paso Robles Wastewater Division's mission is to protect public health and the environment in the most cost-effective manner possible. The Wastewater Division owns and operates 126 miles of sewers and 14 lift stations to collect wastewater from all of Paso Robles and transport it to a wastewater treatment plant at the north end of town, near the Salinas River. Learn more about the Wastewater Collection System.

Wastewater Division Team Group Photo

The Wastewater Treatment Plant

The City's Wastewater Treatment Plant is a physical, biological, and chemical process that currently treats and discharges 2.3 million gallons of wastewater to the Salinas River each day. The Plant operates under NPDES Permit Number CA0047953 (PDF). Actions the City takes to collect, treat, and dispose of City wastewater are detailed in the City's latest annual report (PDF).

Upgraded Treatment Process

In 2016, the City completed a major upgrade of its Wastewater Treatment Plant to a Biological Nutrient Removal process. This new treatment process effectively removes all harmful pollutants from the wastewater and is highly energy efficient. The upgrade project included:

  • New Headworks

  • Rehabilitation of Primary Clarifiers

  • New Pump Station

  • Replacement of Trickling Filters with the Biological Nutrient Removal Process

  • New Secondary Clarifiers

  • Chloramination Disinfection Process

  • System That Generates Power and Heat from Biogas Generated by Digestion of Sludge.

  • New Operations Building with Laboratory

New Tertiary Treatment Facilities

The City has a master plan to produce tertiary-quality recycled water and distribute it to east Paso Robles, where it may be safely used for irrigation of City parks, golf courses, and vineyards. This will Lab Beaker of clean water after tertiary treatment processreduce the need to pump groundwater from the Paso Robles Groundwater Basin and further improve the sustainability of the City's water supply. In 2019, the City completed construction and began operating the first part of this recycled water system, which is filtration and ultraviolet light disinfection at the Plant. These new tertiary treatment facilities produce very high quality recycled water (see photo of sample). The project also included flow equalization basins, a recycled water storage pond and pump station, a nutrient harvesting system, and new maintenance shop.

Overview of WWTP Map with Tertiary Treatment Facility components

The City is presently designing a major distribution system to deliver recycled water to east Paso Robles. The distribution system project will be ready for construction in 2023.

Water & Sewer Utility Services & Fees

For information on connection fees, visit the Building Division's Development Fees page. For monthly fees, visit the Administrative Services Utilities and Billing page.