Got Stormwater? Are You Aware of the City of San Diego Changes at Your Jobsite?

By BIA Stormwater Task Force 
Are you aware of the City of San Diego’s new rules for construction BMPs!


Effective October 1, 2018 the City of San Diego has made effective substantial changes in the Stormwater Standards Manual. Pay particular attention to Part 2, Construction BMP Standards. One of the more significant changes is that of dewatering of contained storm water. Pay close attention to the stringent <20 NTU requirement.


Dewatering of contained storm water must comply with the following:


a) The City must be notified (619-235-1000) or prior to discharging into the street, gutter, or storm drain. The gutter from the discharge point to the inlet must be swept clean prior to discharge.


b) Water discharging from the site must be clear or field-tested and documented to be less than 20 Nephelometric Turbidity Units (NTU) or demonstrated through a drainage study that the project is not causing and/or contributing to exceedances in the receiving water.


c) Discharges from dewatering operations must be directed through an appropriate pollution prevention or treatment system of control measures, such as a filter bag and sediment trap or sediment basin, prior to being discharged from the construction site.


d) Ensure that dewatering discharges do not cause erosion at the discharge point by implementing the Temporary Energy Dissipation BMP.


What does this mean for construction projects within the jurisdiction of the City of San Diego?


It means that risk Level 1 through 3 projects will need to meet discharge requirements more stringent than the Construction General Permit if stormwater is discharged into the city’s MS4 system, which includes curb and gutter. In other words, an unauthorized discharge isn’t exclusive to water entering the storm drain inlet only. As soon as the water hits the curb and gutter, or street it must meet the <20 NTU requirement.


Without an effective combination of erosion AND sediment controls, as well as adequate holding time in a properly sized basins, to allow sediments to fall out, achieving <20 NTUs may be close to impossible. You may need to consider alternative methods, such as a sewer discharge permit, sand filtration systems or an ATS system if achieving <20 NTUs cannot be attained.


Also new as of October 1, 2018 is the City of San Diego’s escalating enforcement and this will need to be covered in a separate writing. Feel free to contact your BIA for more information on BMP & compliance solutions for the rainy season challenges.


We can’t emphasize enough the importance of reading and understanding Part 2 of the City of San Diego’s Storm Water Standards manual, here is the link: