Indoor drains collect water from sinks, toilets, floors and appliances. This water is treated at the wastewater treatment facility. Occasionally, in old buildings, indoor drains can lead to stormwater outflows, which are not treated. City staff can dye test your drains during a visit to determine where they lead.
Outdoor drains and ditches collect water from hard surfaces like roofs, pavement and hard-packed ground. This water is piped through the stormwater system and discharged directly into nearby waterways like creeks, lakes, and marine waters. Storm drains are meant for rain and snow melt only. It's important to keep this water clean.
For printed copies of fact sheets and other resources, or for more information, contact
For business-related stormwater resources, trainings, and more, visit the
Washington Stormwater Center.