Levels of flame retardants in house dust and a transport pathway from homes to the outdoor environment were investigated in communities near the Columbia River in Washington state (WA). Residential house dust and laundry wastewater were collected from 20 homes in Vancouver and Longview, WA and analyzed for a suite of flame retardants to test the hypothesis that dust collecting on clothing and transferring to laundry water is a source of flame retardants to wastewater treatment plants (WWTPs) and subsequently to waterways. Influent and effluent from two WWTPs servicing these communities were also analyzed for flame retardants. A total of 21 compounds were detected in house dust, including polybrominated diphenyl ethers (PBDEs), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB or EH-TBB), bis(2-ethylhexyl) 3,4,5,6-tetrabromophthalate (TBPH), 1,2-bis(2,4,6,-tribromophenoxy)ethane (BTBPE) and decabromodiphenylethane (DBDPE), hexabromocyclododecane (HBCD or HBCDD), tetrabromobisphenol A (TBBPA), and three chlorinated organophosphate flame retardants (ClOPFRs), tris(1,3-dichloro-2-propyl)phosphate (TDCPP or TDCIPP), tris(1-chloro-2-propyl)phosphate (TCPP or TCIPP), and tris(2-chloroethyl)phosphate (TCEP). Levels ranged from 3.6 to 82,700 ng g(-1) (dry weight). Of the 21 compounds detected in dust, 18 were also detected in laundry wastewater. Levels ranged from 47.1 to 561,000 ng L(-1). ClOPFRs were present at the highest concentrations in both dust and laundry wastewater, making up 72% of total flame retardant mass in dust and 92% in laundry wastewater. Comparison of flame retardant levels in WWTP influents to estimates based on laundry wastewater levels indicated that laundry wastewater may be the primary source to these WWTPs. Mass loadings to the Columbia River from each treatment plant were by far the highest for the ClOPFRs and ranged up to 114 kg/yr for TCPP.