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City of Paso Robles
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Wastewater Division Treatment Plant
3200 Sulphur Springs Road
Paso Robles, CA 93446
(805) 237-3865
(805) 237-3886 FAX
Mon-Fri 7am to 3:30pm


Wastewater Treatment Plant
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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 136 miles of sewers and 14 lift stations to collect wastewater from all of Paso Robles and east Templeton 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.

The Wastewater Treatment Plant

The City's Wastewater Treatment Plant is a physical, biological, and chemical process that currently treats and discharges 2.7 million gallons of wastewater to the Salinas River each day.  The Plant operates under NPDES Permit No. CA0047953.  Actions the City takes to collect, treat, and dispose of City wastewater are detailed in the City's latest annual report.

Until recently, the Plant was antiquated and struggled to comply with modern State and Federal water quality regulations. Thanks to the support of the City's many sewer customers, in 2015 the City completed a major upgrade of the Plant to a Biological Nutrient Removal process.  The upgrade project included new headworks, rehabilitation of primary clarifiers, a new pump station, replacement of trickling filters with the Biological Nutrient Removal process, new secondary clarifiers, a chloramination disinfection process, a new effluent polishing channel, and a system that generates power and heat from biogas generated by digestion of sludge.  This new treatment process effectively removes all harmful pollutants from the wastewater and is highly energy efficient. 

The upgraded treatment process enables the City to produce high quality recycled water in the future.  In 2013, the City adopted 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 reduce the need to pump groundwater from the Paso Robles Groundwater Basin and further improve the sustainability of the City's water supply.  

The City is presently constructing additional treatment facilities (filtration + ultraviolet light disinfection) needed to produce tertiary quality recycled water. These facilities will be substantially complete in late 2018. The City is also presently designing a major distribution system to deliver recycled water to east Paso Robles. The distribution system project should be ready to start construction in late 2018.

Water and Sewer Utility Services and Fees

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


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