King CountyFor more information about this layer please see the GIS Data Catalog . Tank Component Types---Wet (Permanent Pool): A tank that features a permanent pool of water. They are designed to optimize water quality by providing long retention times (on the order of a week or more) to settle out particles of fine sediment to which pollutants such as heavy metals adsorb, and to allow biologic activity to occur that metabolizes nutrients and organic pollutants.---Infiltration: A tank that is designed to use the hydrologic process of water soaking into the ground (commonly referred to as percolation) to dispose of stormwater.---Detention: Detention tanks temporarily store stormwater and typically releases flow over a few hours or a few days.---Combined (Wet and Detention): Detention tanks contain a permanent pool of water, but also have volume for temporary storage beyond the permanent pool.ArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/2fa77cb87ca84e60a5cdd3d57e560269_0engKing County GIS Open DataPublicControl Tank [Washington (State)--King County]Web servicesWashington (State)--King CountyWashington (State)Last Modified: 2026-01-08