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The South Bay International Wastewater Treatment Plant Project

Note: EPA no longer updates this information, but it may be useful as a reference or resource.


Since the 1930's, raw sewage flowing into the United States from Mexico has posed a serious threat to public health and the environment in the South Bay communities of San Diego. This problem has gradually worsened over the years with the substantial growth of Tijuana's population and industrial sector. Large volumes of untreated wastewater still flows into the Tijuana River valley today.

In July 1990 the U.S. and Mexico agreed to build an International Wastewater Treatment Plant (IWTP) on the U.S. side of the border as part of a regional solution. This facility is now treating sewage flows that exceed the capacity of the existing Tijuana sewage treatment system. In doing so, it plays a key role in restoring the environmental quality of the Tijuana River valley and safeguarding the health of its residents.

Arial view of IWTP

Related Documents

Record of Decision for Secondary Treatment at IWTP
... announced 12/8/99 by EPA and the International Boundary and Water Commission

Final Supplemental Environmental Impact Statement -- Long Term Treatment Options
... with an extended public comment period

IWTP Draft Supplemental Environmental Impact Statement - Long Term Treatment Options
... includes the SEIS Fact Sheet in English and Spanish, the SEIS Executive Summary, and a Portable Document Format version of the SEIS.

Supplement to the Final Supplemental Environmental Impact Statement -- Interim Operations

IWTP Supplemental Environmental Impact Statement - Interim Operation
... includes the SEIS Fact Sheet and Executive Summary along with downloadable files of the draft and final SEIS, as well as the Record of Decision.

IWTP Fact Sheets and Project Updates
... an overview of the project and periodic updates

Contact Information

Elizabeth Borowiec (borowiec.elizabeth@epa.gov)

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