We used field surveys to compare coarse filter-large water volume samples (hereafter large volume filter samples) vs. fine filter-small water volume samples (hereafter small volume filter samples) for detection and quantification of bull trout (Salvelinus confluentis). We collected eDNA water samples in 2016 from three long-term fish monitoring sites in tributary streams (~ 2nd order) in the Flathead River, MT with low densities (less than 1 fish per 100 m2) of juvenile bull trout We report the quantity of bull trout DNA detected.