Clark County, Washington: drinking water report. Clark County sits across the Columbia River from Portland, Oregon, with a population of about 510,000…
Clark County sits across the Columbia River from Portland, Oregon, with a population of about 510,000 centered on Vancouver. The county draws water from multiple sources – the City of Vancouver uses a wellfield tapping the Troutdale Aquifer, while other communities pull from the Lewis River, East Fork Lewis River, and smaller groundwater systems. The proximity to Portland means Clark County shares many regional water quality challenges while operating under Washington's separate regulatory framework.
The former Alcoa/Vancouver aluminum smelter site and Portland's industrial corridor across the river contribute to a regional contamination footprint. The EPA's UCMR5 monitoring detected PFAS at sampling points in Clark County water systems. According to the Washington Department of Ecology's 2024 PFAS investigation, the Pearson Air Museum/former Army airfield in downtown Vancouver has confirmed PFAS contamination from historical operations.
Vancouver's Troutdale Aquifer is productive but vulnerable. The aquifer sits beneath an urban landscape with industrial facilities, gas stations, and transportation corridors that create multiple contamination pathways. A 2023 Washington DOH report documented that two public water systems in Clark County exceeded the state's PFAS action levels, which at 10 ppt for individual PFAS compounds are stricter than the federal MCLs.
Washington's stricter PFAS standards mean Clark County systems may be flagged for action at levels that would pass in other states. That is actually good news for residents – it means contamination is being caught earlier.
Check your water to see what has been detected in your specific service area. For PFAS, reverse osmosis or granular activated carbon filters certified to NSF 53 are effective. Our water filter guide compares options by real removal rates. Pull your detailed report for historical data, and visit our Washington page for statewide patterns.