Whatcom County, Washington: drinking water report. Whatcom County on Washington's northern border has about 229,000 residents, with Bellingham as the
Whatcom County on Washington's northern border has about 229,000 residents, with Bellingham as the county seat. The City of Bellingham draws from Lake Whatcom, while other communities rely on groundwater and smaller surface sources. Lake Whatcom serves as both the drinking water supply and a recreational lake – a dual use that creates inherent tension between development and water quality protection.
Lake Whatcom's water quality has been declining. According to the Washington Department of Ecology's 2024 lake monitoring report, dissolved oxygen levels in the lake's deeper waters have been dropping, and phosphorus concentrations have increased by 25% over the past two decades. Residential development along the lake shore – septic systems, impervious surfaces, stormwater runoff – drives the nutrient loading.
The Bellingham International Airport has documented AFFF use. Washington DOE's 2024 PFAS investigation found PFOS at 11 ppt in monitoring wells near the airport. The former Oeser Company wood treatment facility on Bellingham Bay contributed pentachlorophenol and dioxin contamination to the waterfront area.
Lake Whatcom's declining trend means Bellingham's source water quality is slowly deteriorating. Treatment handles current conditions, but the long-term trajectory warrants community attention and household-level preparedness.
Check your water for current data. A carbon filter addresses taste and disinfection byproducts from treated lake water. For PFAS, reverse osmosis provides targeted protection. Our water filter guide covers lake-water-specific systems. Pull your detailed report for trends, and visit our Washington page for statewide patterns.