Residential customers have been paying the city to manage that excess water for years and Mayor Michael Nutter says commercial properties need to contribute more, too.
He says many large lots don't manage their storm water well.
"That surcharges our system, causes sewer backup and flooding in basements in many parts of the city."
The City's Water Department says the charge will be effective July 1st.
It also says technically it's not a new fee it was previously included in the Service Charge portion of non-residential bills. And while the amount was previously based on meter size, it will now be based on property size.