The MSAR Bacteria TMDL was established due to bacterial contamination in: Santa Ana River, Reach 3; Chino Creek, Reaches 1 and 2; Mill Creek (Prado Area); Cucamonga Creek, Reach 1; and Prado Park Lake.
The MSAR Bacteria TMDL was adopted on August 26, 2005, through Resolution R8-2005-0001. They were then approved by the Office of Administrative Law (OAL) on September 1, 2006, followed by the US Environmental Protection Agency on (US EPA) May 16, 2007.
January 9, 2023 - CEQA Scoping
CEQA Scoping Meeting Public Notice
January 27, 2026
TMDL Technical Report: Proposed Revisions to the Middle Santa Ana River Watershed Bacterial Indicator TMDLs
Tentative Resolution No. R8-2026-0014
Draft Amendment to the Santa Ana Region Basin Plan - Clean
Draft Amendment to the Santa Ana Region Basin Plan - Redline
Notice of Public Hearing and Comment Period
Aviso De Audiencia Publica Y Periodo De Comentarios
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For more information, please contact Lauren Hubbell at (951) 320-6375
(Page last updated 2/12/26)
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