Sanitary Sewers

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If you observe any overflowing manholes, sewer line back ups, obstructions, or missing manholes/storm drain grates, please report them to 538-2415 immediately. For emergencies after 3:30pm, weekends, or holidays please call 538-2448.


The City of Oroville owns and operates a sanitary sewer collection system for the benefit of residents and businesses in the Oroville city limits. In addition to the City's sanitary sewer system, Thermalito Water & Sewer (TWS) and Lake Oroville Area Public Utilities District (LOAPUD) operate a separate sanitary sewer system. Please consult our utility districts map to determine which sewer district operates in your area. The sanitary sewer crew maintains approximately 66 miles of sanitary sewer gravity mains with approximately 1,200 manholes and over 2.1 miles of force main. The City also maintains seven sewer lift stations, and two flow meters. Engineering as-builts of Oroville's Sanitary Sewer Infrastructure can be found here.

Important Information

If you observe sewerage overflow on your property immediately contact the city before you contact a plumber. It is possible that the overflow on your property is due to an obstruction in the City sewer main. If the obstruction is located in the city sewer main it is the responsibility of the city to remove the obstruction with no cost to you. Please report overflows to (530) 538-2415.

Sanitary Sewer Master Plan

The City of Oroville is in the process of creating a Sanitary Sewer Master Plan. Please check back in the future as this master plan will be posted on this website. The purpose of the master plan is as follows:

  • Evaluates the capacity of the existing sanitary sewer collection system using dry and wet weather flows
  • Evaluates the City's sanitary sewer operation and maintenance activities
  • Develops a capital improvement program that provides the City with a reliable plan to mitigate existing system deficiencies and expand the wastewater collection system to service future customers
  • Determines the revenue and rates necessary to finance the capital improvement program
  • Develops a Sewer System Management Plan (SSMP) conforming to the requirements of the State Water Resource Control Board (SWRCB)

New Sewer Pipe in a trench


Manhole Base