The Los Coches Road runoff diversion project proposes to install an underground treatment facility to remove pollutants found in storm water runoff. The system will consist of an off-line trash capture device with a connection to the nearby sanitary sewer.


Conceptual rendering of a potential trash capture device.

Community: Lakeside

Drainage Area Treated: 192 acres

Pollutants Removed: Trash, sediment, debris, and bacteria.


A conceptual rendering of a trash capture device is shown in the adjacent image. The specific device to be used for the project has not yet been selected.

What to Expect

During construction, the County will make every effort to minimize disruptions along Los Coches Road and Via Diego. All construction will occur in the public road right-of-way to avoid impacts to private property owners. There will be temporary impacts to utilities, and to both vehicular and pedestrian traffic. Traffic control measures, including signage placed prior to and during construction, will be implemented to ensure the safety of our customers.

It is estimated that construction of the project will begin in Summer 2023 and be completed in Spring 2024. Please note that construction dates are subject to change due to compliance requirements, inclement weather, and/or other unforeseen circumstances.


Water Quality Improvements

During periods of wet weather, runoff flows in the storm drain system will be treated by a trash capture device, which will remove trash, debris, and sediment before they are discharged into nearby Los Coches Creek.

In periods of dry weather, any runoff flows treated by the trash capture device will be diverted to the sanitary sewer for further treatment.


Pedestrian Improvements

A new pedestrian refuge island, with a raised curb, will create a safer environment for pedestrians looking to cross Via Diego. A retrofitted curb ramp and curb return are also included in the project plans. 


Future Water Supply Benefits

The Los Coches Road runoff diversion project will serve as a pilot project, evaluating the potential to combine water quality treatment benefits with water supply benefits. Beginning in 2025, a portion of the County’s wastewater flow will be directed to the East County Advanced Water Purification Project, which is a potable water reuse project that will use advanced treatment technologies to treat wastewater to drinking water standards. Since this project will be diverting dry weather runoff flows to the sanitary sewer, it will be contributing to local water supplies that could be treated and reused.

Preliminary estimates show that the project could contribute 1.3 million gallons per year to local water supplies.