Comprehensive budgets of total suspended solids (TSS), total phosphorus (TP), total zinc (the most prevalent metal in urban runoff), and fecal coliforms (FC) were developed for two palustrine freshwater wetlands in Washington, USA. These budgets were based on input (inflow, precipitation, groundwater) and output (outflow, evaporation). One wetland received runoff from a primarily urbanized watershed (187 ha), whereas the other watershed (87 ha) was mostly rural and forested. Annual loadings to the urban wetland for TSS, TP, and zinc were 107, 0.63 and 0.43 kg ha - 1 yr - 1 , respectively, based on watershed area. Corresponding loadings to the nonurban wetland were 30, 0.62 and 0.08 kg ha - 1 yr - 1 . High TP input from groundwater at the nonurban wetland (82% of the TP input) resulted in overall loadings comparable to the urban wetland. Fecal coliform loadings were 4.2 10 1 0 and 1.4 10 9 organisms ha - 1 yr - 1 for the urban and nonurban wetlands, respectively. Mean annual removal percentages (over the two-year study period) for TSS, TP, zinc, and FC were estimated at 14, 8, 31, and 49%, respectively in the urban wetland (2 ha). Corresponding removal rates in the nonurban wetland (1.5 ha) were 56, 82, 23, and 29%, respectively. Pollutant removal was influenced by season, flow conditions, residence time, pollutant source (surface versus groundwater), and pollutant state (solid versus dissolved). Results for the nonurban wetland showed that groundwater inputs were significant for TP loadings and removal.