Stormwater to public rainwater channel that is connected to sea

Our building is connected to a public rainwater channel which is placed out of the LEED boundary, the rainwater channel is connected to the sea. Buildings in this area are connected to this public channel and are supposed according to the local authorities. Our project is a new construction office building and not on a campus project. I came across this definition "Projects with stormwater control measures outside the LEED project boundary may be accepted if the measures appropriately take into account neighboring facilities by demonstrating that the existing stormwater management systems that serve the LEED project boundary meet the LEED requirements for all areas within the site serviced by those systems. " I am not sure weather that means that the whole area needs to comply with 90% rainwater treatment and remove 80% of TSS, it could also mean that the channel shall have enough capacity to take all the rainwater from all the buildings that are connected to it. As our project boundary does not include the public rainwater channel and we are not talking about a campus project, we do not have any chance to influence how the other buildings that are already connected to the system treat the rainwater before it is discharged into the channel. Would we compliant with the credit when we discharge our rainwater into the public channel?