Newport Bay Fecal Coliform TMDL

Background Information

Fecal coliforms are a type of fecal indicator bacteria (FIB) found in the digestive systems of humans and animals that are monitored worldwide to evaluate water quality. The presence of fecal coliforms in surface waters is used as an indicator of human pathogens, which can cause illness in swimmers and recreators. FIBs have historically been used as indicators of human pathogens because they are easier and less costly to measure than pathogens themselves. Recently the choice of FIBs have shifted to E. coli for freshwater and Enterococci for marine waters. Therefore, Newport Bay Fecal Coliform TMDL is being revised to reflect the latest science and to be consistent with state and federal guidance.
Newport Bay Fecal Coliform TMDL
Regulatory Description


In 1999 the Santa Ana Regional Water Quality Control Board adopted a Total Maximum Daily Load (TMDL) for fecal coliforms in the Newport Bay. Given the complexity of the problem, the paucity of relevant data on bacteria sources and fate, the expected difficulties in identifying and implementing appropriate control measures and uncertainty regarding the nature and attainability of the shellfishing beneficial use in the Bay, a prioritized, phased approach to the control of bacterial quality was developed. The phased approach is intended to allow for additional monitoring and assessment to address areas of uncertainty and for future revision and refinement of the TMDL.

Recent Developments

The State Water Resources Control Board is proposing a statewide program to protect recreators from effects of pathogens in water.  The program includes changes to pathogen indicator bacteria and objectives for marine and fresh water. 

Basin Plan Amendments for the Santa Ana Region include changes to pathogen indicator bacteria objectives in freshwater, as well as REC-1 beneficial use status for the Santa Ana Delhi Channel.  The Amendments were recently approved by the State Board, and approved by the EPA.  These changes will eventually apply to Orange County's stormwater discharge permit. 

A public stakeholder process will be taking place through 2018 to address bacterial water quality regulations in the Newport Bay with respect to Recreational and Shellfish Harvesting Beneficial Uses

Data Collection and Reporting

Per California Water Code (Section 13267), the County of Orange and the Cities of Costa Mesa, Irvine, Lake Forest, Newport Beach, Orange, Santa Ana, and Tustin, the Irvine Ranch Water District (IRWD) and the Irvine Company are currently supporting studies and monitoring in the Bay towards developing a TMDL implementation plan to achieve the TMDL targets.

Monitoring and study efforts have included the development and implementation of a routine monitoring program, development of a water quality model for bacterial indicators, recreational and shellfish harvesting beneficial use assessments, a human health risk assessment, evaluation of the vessel waste program, and source identification and characterization of the Dunes Resort, agricultural, urban and natural runoff sources.  The County of Orange, on behalf of watershed stakeholders, implements a routine monitoring program to determine compliance with bacterial water quality objectives in the Bay. Orange County Health Care Agency collects at least five samples per 30-day period at 35 stations throughout Newport Bay and publishes these data on-line at

Newport Bay Fecal Coliform Annual Data Reports, which report data from the water quality monitoring program, along with analysis on attainment of the water quality objectives, and information on additional implementation tasks, are found in the OC Public Works Document Library (to find the reports: in the name column, type fecal coliform).

Watershed cities and the County report their BMPs in the Unified Program Effectiveness Assessment Annual Reports

Efforts to control bacteria in the Newport Bay watershed specifically are described in the Newport Bay 2016 Summary of Management Activities

Public involvement

You can help in efforts to improve water quality of the Newport Bay by:

  • Picking up your dog's waste