In parts of Portland with a combined sewer system, rain gardens, green streets and other green infrastructure reduce stormwater flow to the treatment plant, help prevent flooding and sewer backups in basements, and reduce the costs to sewer ratepayers of protecting water quality and managing city infrastructure.
It costs sewer ratepayers about $3 a gallon to store, pump and treat rainwater. The system operates more efficiently when more rainwater soaks into the ground rather than flowing to the treatment plant.
Portland invests in green infrastructure around the city to manage stormwater and improve water quality in local streams. This helps improve habitat for native fish and wildlife. See Portland’s Watershed Report Cards to learn more.