Portland Code for Stormwater Management

This rule establishes requirements for the management of stormwater, groundwater, and drainage to protect and improve water quality in the City of Portland. All development, redevelopment, and improvement projects within Portland on private and public property and in the public right-of-way that create or replace 500 ft2 or more of impervious area must meet requirements specified under the Stormwater Management Manual.
(a) The Stormwater Management Manual establishes pollution reduction and flow-control standards, and requires the use of green infrastructure to the maximum extent practicable before other measures can be considered.
(b) The City of Portland’s Stormwater Management Manual prioritizes onsite infiltration and the use of vegetated facilities.