Drinking Water Source
Where does your water come from?
The City of Vancouver gets its drinking water, or potable water, from three distinctly different regional aquifers. All water supplies come from wells tapping three underground aquifers – the Orchards, Troutdale and the Sand-and-Gravel aquifers. These aquifers make up the Troutdale Aquifer System which covers most of Clark County. The groundwater system was designated a Sole Source Aquifer in 2006 due to its critical nature in providing water supplies to you and your neighbors.
An aquifer is an underground layer of unconsolidated rock or sand that is saturated with usable amounts of water. Aquifers, which store and carry water, form significant natural water supplies. Recharge areas are important to a healthy aquifer. In a recharge area, water seeps into the earth and down to the aquifer, helping recharge these vital natural resources.
The upper aquifers – the Orchards Aquifer (Upper and Lower) and the Upper Troutdale Aquifer – are the principal municipal water supply aquifers in Clark County. Where these two shallow aquifers are not present, the deeper Sand-and-Gravel Aquifer is a significant source of groundwater. The Sand-and-Gravel Aquifer also is a source of supply for several City of Vancouver and Clark Public Utilities wells, in addition to other regional municipalities and industries.
The City’s Utility tracks water consumption and levels closely at all well stations, as required by state law. In addition, the Utility keeps a close eye on yearly rainfall averages, which are important to recharging our aquifers.
The City of Vancouver is committed to ensuring our water resources are used efficiently to protect and preserve the high quality of life of current residents and generations to come.
City Water Supply Aquifer Descriptions
- The Upper Orchards Aquifer is recharged primarily by infiltration of rainfall. As a result, the quantity of water available from the aquifer on a sustainable basis is dependent on the local precipitation pattern. Levels in this aquifer are closely monitored.
- The Lower Orchards Aquifer supports wells at three of the City’s highest volume production water stations. The water levels in this aquifer are slightly above sea level and close to the stage height of the Columbia River. The Columbia River is believed to provide downstream hydraulic stability for the Lower Orchards Aquifer, and the potential yield from properly located well fields in the Lower Orchards Aquifer is strongly drought-resistant. Historically, water levels in this aquifer fluctuate very little, even under heavy use. Since construction of the City’s oldest wells in the 1940s, static water levels have shown little or no decline.
- The Upper Troutdale Aquifer is recharged from a downward movement of groundwater from the overlying aquifers, including the Upper Orchards Aquifer. Well yields in the Upper Troutdale Aquifer are typically lower than those for the Orchards aquifers.
- The Sand-and-Gravel Aquifer is a deep aquifer that underlies a large portion of the greater Vancouver area. It has a massive volume of stored water and is believed to receive recharge via infiltration from shallower aquifers and perhaps directly from the Columbia River, some distance upstream of the City.